1

FOOD ADVISORY COMMITTEE AND DIETARY

SUPPLEMENTS SUBCOMMITTEE

FURAN MEETING

Tuesday, June 8, 2004

1:55 p.m.

Bethesda Marriott

Grand Ballroom

5150 Pooks Hill Road

Bethesda, Maryland

PARTICIPANTS

Food Advisory Committee

Sanford A. Miller, Ph.D., Chairman

Linda Reed, Acting Executive Secretary

Douglas L. Archer, Ph.D.

Patrick S. Callery, Ph.D.

Goulda A. Downer, Ph.D.

Johanna Dwyer, D.Sc, RD

Jean M. Halloran

Norman I. Krinsky, Ph.D.

Daryl B. Lund, Ph.D.

Margaret C. McBride, M.D.

Mark F. Nelson, Ph.D.

Robert M. Russell, M.D.

Carolyn I. Waslien, Ph.D., R.D.

Contaminants and Natural Toxicants Subcommittee

Alex D.W. Acholonu, Ph.D.

Marion F. Aller, D.V.M., DABT

George M. Gray, Ph.D.

Ken Lee, Ph.D.

Henry B. Chin, Ph.D.

Temporary Voting Member

P. Joan Chesney, M.D.

FDA

Dr. Henry Kim

C O N T E N T S

PAGE

Welcome and Introductions

Sanford A. Miller, Ph.D., Chair 4

Conflict of Interest Statement

Linda Reed, Acting Executive Secretary, FAC 6

Opening Remarks

Nega Beru, Ph.D. 10

Scientific Overview of Furan in Foods

Analytical Methods/Occurrence

Dr. Kim Morehouse 22

Exposure

Jeremy Mihalov 36

Formation

Dr. Don Forsyth 49

Questions of Clarification 58

Scientific Overview of Furan in Foods

Dr. Glenda Moser 69

Questions of Clarification 86

Public Comment 98

Summary and Charge to the Committee

Dr. Terry Troxell 98

Questions of Clarification 105

Committee Discussion and Recommendations 115

P R O C E E D I N G S

Welcome and Introductions

DR. MILLER: I think I would like to get

started to enable us to finish on time and give

people a chance to make their planes, and so on.

First of all, let me welcome the new

members of Food Advisory Committee meeting for this

afternoon's session, which will deal with furans

and the data necessary in order to estimate the

risk of furans in food.

For the record, when I call your name, I

going to introduce the new members of the

committee. This meeting is being held in

conjunction with the Contaminants and Natural

Toxicants Subcommittee of the Food Advisory

Committee, and there several members of that

committee that will be sitting with us in our

deliberations.

When I call your name, will you please

just repeat your name and the institution with

which you are associated.

First, Dr. Acholonu.

DR. ACHOLONU: My name is Alex Acholonu,

Alcorn State University, Mississippi.

DR. MILLER: Dr. Aller.

DR. ALLER: Marion Aller with the Florida

Department of Agriculture and Consumer Services.

DR. MILLER: Dr. Gray.

DR. GRAY: George Gray with the Harvard

School of Public Health.

DR. MILLER: Dr. Lee.

DR. LEE: Ken Lee with Ohio State

University.

DR. MILLER: Dr. Chin.

DR. CHIN: Henry Chin with the National

Food Processors Association.

DR. MILLER: Dr. Chesney.

DR. CHESNEY: I am Joan Chesney. I am

Professor of Pediatrics and Infectious Diseases at

the University of Tennessee and also the title you

see on the roster at St. Jude. I am also here

representing the FDA Pediatric Drug Subcommittee.

DR. MILLER: Thank you.

Since we have some new members, we are

required to repeat the discussion of conflict of

interest for this particular issue on furans.

Linda Reed, who is Acting Executive

Secretary of the Food Advisory Committee, will read

them.

Conflict of Interest Statement

MS. REED: Good afternoon, everyone. As

Chairman Miller indicated, I am Linda Reed, the

Acting Executive Secretary of the Food Advisory

Committee meeting. I would like to welcome

everyone and particularly our member from CDER.

I need to read the conflict of interest

statement into the record again.

The authority to grant permission to

borrow Special Government Employees currently

serving on an advisory committee in a sister

center, in this case, the Center for Drug

Evaluation and Research, is granted to the

Associate Commissioner for External Relations, Mr.

Peter Pitts.

Relying on that authority, Mr. Pitts has

signed a memorandum granting permission for Dr. P.

Joan Chesney to serve as a temporary voting member

for this portion of the meeting concerning furan on

June 8, 2004. Dr. Chesney will represent, as she

just indicated, the Pediatrics Advisory

Subcommittee of the Anti-Infective Drugs Advisory

Committee.

Because of the breadth of topics to be

discussed at this meeting, all of the members and

temporary voting member have been screened for any

and all financial interests associated with

regulated industry.

Based on this review, FDA has determined

in accordance with 18 U.S.C. Section 208(b)(3) to

grant general matters waivers to Dr. Marion Aller,

Dr. Douglas Archer, Dr. Johanna Dwyer, Dr. George

Gray, Dr. Norman Krinsky, Dr. Margaret McBride, Dr.

Sanford Miller, Dr. Robert Russell, and Dr. Carolyn

Waslien.

The granting of these waivers permits

these individuals to participate fully in the

matters before the committee. Copies of the waiver

statements may be obtained by submitting a written

request to the agency's Freedom of Information

Office, Room 12A-30 of the Parklawn Building.

In an effort to enhance consistency within

FDA, the agency has recently adopted a policy

whereby all public commenters will be asked to

report any personal financial interests that could

be affected by the committee's deliberations. A

copy of the policy was provided to any individual

who registered to make comments at this meeting.

Additional copies of the policy may be obtained

from the registration desk.

Similarly, we have asked all of our guest

speakers to complete a financial interest and

professional relationship certification for guests

and guest speakers to identify any potential

conflicts of interest.

Dr. Don Forsyth and Dr. Glenda Moser will

be the guest speakers at this portion of the

meeting. Both have indicated they have no

financial interests in the food industry.

I would like to thank for your attention

and I will turn the meeting back over to Dr.

Miller.

Thank you.

DR. MILLER: Thank you, Linda.

As a matter of procedure, each of the

speakers have been assigned a time for their

presentation, and in order for us to make certain

we get through the presentations, and most

important of all, the discussion, I intend to be as

ruthless as I can in keeping the time.

We have several limitations on our time.

For one thing, we have to be out of here by 6

o'clock at the very latest. Otherwise, as I

indicated this morning, we may be involved in

somebody else's wedding.

Also, there are some of you who have

planes to catch, and in order for the committee to

complete its business, which will be explained in

just a moment, it is important that we stick to the

time schedule.

The first presenter is Dr. Nega Beru of

the FDA, who will provide the background and

discuss the charge to the committee.

Opening Remarks

DR. BERU: Thank you, Dr. Miller, and good

afternoon. My name is Nega Beru. I am the

Director of the Division of Plant Product Safety in

CFSAN's Office of Plant and Dairy Foods.

My purpose here today is to provide you

with some of the background on furan in foods to

set the stage for the scientific overviews that

will follow immediately.

I will also lay out what input we are

seeking from the committee.

The structure of furan is depicted on this

slide. It is a 5-member O-ring with two double

bonds. It goes by a number of names as shown on

this slide also, has a molecular weight of 68, a

melting point of -85.6 degrees Celsius, and a

boiling point of 31 degrees Celsius.

This last property, it is fairly volatile,

may be important with respect to how much furan

consumers are exposed to in foods as consumed.

Furan is a colorless liquid that is used

in some segments of the chemical manufacturing

industry. It is used, for example, as a solvent

for resins and in the manufacture of lacquers.

It was the subject of a 2-year bioassay by

the National Toxicology Program in 1993. As a

result, it is listed in the Department of Health

and Human Services report on carcinogens, because

it was found to cause cancer in rodents in the NTP

study.

Furan is formed in food during traditional

heat processing techniques, such as cooking and

canning. Its mechanisms of formation are beginning

to be elucidated, and there appear to be a number

of them.

Later in this session, Dr. Don Forsyth

from Health Canada will present to you their

studies on mechanisms of formation of furan in

foods.

The discovery of furan in foods is not

new. Furan has been reported in a small number of

foods starting as early as the 1960s, although very

little quantitative data exists in the literature.

Furan was found in coffee, canned meat,

baked bread, cooked chicken, sodium caseinate,

hazel nuts, soy protein isolates, hydrolyzed soy

proteins, rapeseed protein, fish protein

concentrates, and caramel.

What is new here is that FDA has developed

a quantitative method to measure low levels in food

and has found that furan forms in a wider variety

of foods than previously thought including in some

baby foods.

In addition to FDA, Health Canada and

NFPA, together with some of its members, are

investigating furan levels in foods, and, in fact,

FDA, Health Canada, and NFPA are also currently

collaborating In a round robin evaluation of the

method that was developed by FDA.

FDA's finding was made during

investigations aimed at confirming a report in the

scientific literature that furan forms when apple

juice is irradiated. As part of that

investigation, a number of non-irradiated, but

processed foods were also evaluated using a

semi-quantitative method.

In the exploratory survey we posted on the

web on May 7, we used a more refined quantitative

method. FDA initially concentrated on foods that

appeared to have high levels during the initial

screen using the semi-quantitative method. FDA

also analyzed foods that didn't necessarily have

high levels in the initial survey, but could

potentially result in high exposures based on

consumption data.

For each type of food, foods were obtained

from two to three manufacturers, and, in addition,

to get at the lot-to-lot variation, two lots were

examined per food.

Foods that were tested include baby foods,

such as apple juice, applesauce, sweet potatoes,

carrots, and green beans, infant formulas, both

liquid and powder, and adult foods, such baked

beans, soups, chilis, spaghetti sauce, tuna,

coffee, and chicken broth.

Over 160 samples were tested in the

exploratory survey including replicas of the same

brand or product, and the results ranged from

nondetectable to approximately 100 parts per

billion furan.

Right after my presentation, Drs. Kim

Morehouse and Jeremy Mihalov will present more

detailed results of the survey, as well as the

exposure assessment that was based on the results.

FDA made the data collected in this

exploratory survey public on May 7 by posting them

on the FDA's web site. At the same time, we posted

on the web a detailed description of the method

used to analyze the food samples, as well as a set

of questions and answers on the issue of furan in

foods.

FDA also issued two notices in the Federal

data on various aspects of furan in foods, which I

will go into a bit later. The other was to

announce this very meeting of the Food Advisory

Committee and the Contaminants and Natural

Toxicants Subcommittee.

When we announced the data to the public,

we did so with a number of message points. Of

course, we said that finding furan in foods is a

concern because based on studies in rodents, furan

is a potential carcinogen in humans.

At the same time we made it clear that

furan certainly did not appear suddenly in food,

its occurrence in food has been reported before.

What is new here is the discovery in a broader

variety of foods than previously thought including

some baby foods.

We also said that this discovery is not an

immediate public health concern. This was based on

our preliminary exposure assessment and a National

Academy of Science's review of the toxicology of

furan done for NASA, and this review is in your

briefing books, which concluded that, one, the

weight of the evidence suggests that furan is an

indirect carcinogen, and, two, calculated and no

observable adverse effect level of 80 mcg/kg body

weight per day.

Nonetheless, we said that there are many

questions that must be answered to improve the risk

analysis. Thus, we said that we intend to conduct

an expanded survey including foods as eaten in

order to determine exposure and risk to consumers

more accurately.

We also said that we will look at what

additional studies are needed to determine furan's

potential risk to human health, as well as studies

on mechanisms of formation and reduction methods if

the risk assessment warrants such studies.

Finally, we said that we will seek input

from our Food Advisory Committee and Contaminants

and Natural Toxicants Subcommittee on what data are

needed to fully assess the risk posed to consumers

by furan in foods, hence, this meeting.

We intend to evaluate all the available

data including input from this meeting, and develop

an action plan to address the issue of furan in

food. The action plan will certainly include an

expanded survey of foods, but may also include

mechanisms of formation/reduction in foods, as well

as toxicity studies to address mechanism and dose

response.

In the call for data we issued on May 7,

we asked for data in several areas. With respect

to occurrence of furan in foods, we asked for data

on the particular foods in which furan occurs and

the levels in these foods, the formation and

occurrence of furan in home-prepared foods as

opposed to, say, manufactured foods, and on

environmental sources of furan in which a typical

consumer is likely to be exposed.

With respect to mechanisms of formation,

we asked for data on possible mechanisms of

formation, as I mentioned earlier, we wrote a

letter here about studies that Health Canada

conducted on mechanisms on formation.

We also asked for data on variables that

enhance or mitigate furan formation in foods, on

the stability or dissipation of furan in foods, and

on the effect of post-production practices, such as

consumer heating of canned foods on the furan

levels in foods.

With respect to toxicology of furan, we

requested data on mechanism of furan toxicity,

mutagenicity, and carcinogenesis, on reproductive

and developmental toxicology, and on metabolism of

furan in vivo including characterization of any

reactive metabolites, and the role of such

metabolites in producing furans adverse effects

including carcinogenesis.

We also asked for data on the diversity of

furan pharmacokinetics in humans or the alteration

of furan metabolism as a result of dietary,

medical, or environmental interactions, and data on

whether sub-cytotoxic doses of furan produce any

adverse effects, such as a change in enzyme

activities or ATP levels.

Importantly, we asked for data on the

effects of furan at doses lower than those used in

the 1993 NTP study in order to accomplish the

following objectives:

1. To establish a dose-response curve for

the various toxicological endpoints.

2. To determine whether furan toxicity,

including carcinogenesis, is a threshold dependent

event.

3. To determine whether the carcinogenic

activity of furan is secondary to its hepatotoxic

effects.

Last, FDA is also asking for data on the

mutagenicity of furan in the TA100 strain in the

Ames test, and the behavior of furan in other in

vivo assays for mutagenicity or toxicity.

In the Federal Register notice call for

data, we asked that data and comments be submitted

to FDA by July 9, 2004. We also said that we would

share with the committee and the subcommittee any

data or comments we received by June 1.

To date, we have not received any data on

any of the areas we specified in the Federal

That comment was from Dr. James Coglin [ph],

president of Coglin & Associates, a consulting firm

on food, chemical, and environmental toxicology and

safety.

The comment describes work done on various

heat-induced heterocyclic compounds including furan

as antioxidants and urged the committee and

subcommittee to consider the beneficial health

protective effects of such compounds in evaluating

the safety of furan in foods.

This brings me to the charge and the

question we are posing to the committee. This, by

the way, are found in Tab 2 of your briefing

packages.

The Food Advisory Committee and

Contaminants and Natural Toxicants Subcommittee are

being asked to provide input on data that would be

helpful for further evaluation of the potential

risks posed by the presence of furan in foods.

Essentially, this is the question we are

asking the committee. Taking into consideration

the data needs already identified by FDA in the

Federal Register notice requesting data on furan,

and the presentations you are about to hear at this

meeting, are there any additional data that are

needed to fully assess the risk of furan in foods?

With that I will end my presentation. I

trust this will provide an adequate background for

the more detailed presentations that follow, and I

thank you for your attention.

DR. MILLER: Are there any questions for

clarification? Dr. Dwyer.

DR. DWYER: I wasn't clear from the data

needs if you are also considering doing home-cooked

foods, for example, if I made a sweet potato pie at

home, are you planning on doing those, as well?

DR. BERU: I think in the long run, we

want to do that, and perhaps even consider adding

furan to the total diet study. Certainly, we have

done some preliminary work on home cooking in terms

of what dissipation of furan may take place during

normal home preparation of meals of canned or

jarred foods, and Dr. Morehouse will present some

of those data later.

DR. MILLER: Dr. Callery.

DR. CALLERY: Are you planning to also do

the Ames test on metabolites of furan, especially

metabolites that may have some predicted

toxicology?

DR. BERU: Well, at this point we are sort

of in a data collection mode. We want to see what

work has been done out there, and certainly we

intend to do what we can to fill the data gaps

including those studies.

DR. MILLER: Thank you.

We next have three papers dealing with

overview of furan in foods, the first presented by

Dr. Kim Morehouse from FDA. Ten minutes.

Scientific Overview of Furan in Foods

Analytical Methods/Occurrence

DR. MOREHOUSE: Hello. My name is Kim

Morehouse and I am a research chemist with the

Office of Food Additive Safety, Division of

Chemistry Research and Environmental Review. My

collaborators on this project have been Ms.

Patricia Nyman, Mr. Timothy McNeal, and Dr. Gracia

Perfetti.

Today, I am going to present some data

that we have obtained on furan in foods and sort of

explain to you why we got into this in the first

place, even a little bit more than what Dr. Beru

has presented already.

As was noted earlier, during our

investigation of the possible formation of furan by

ionizing radiation, we noted that heating the

sample caused an increase in the amount of furan

that was detected.

This increase was not due in an increase

in the volatility of the furan, but rather was

indeed due to generation of furan.

We also noted the presence of furan in

pasteurized apple juice that we had purchased

locally at a store, but that furan was not present

in apple juice that we prepared fresh in our

laboratory.

This led us to investigate the presence of

furan in heat-processed foods, and we started

looking at various foods. Originally, we were just

looking at it from the standpoint of comparing

radiation treatment to heat treatment of foods, so

we were doing a very random sampling of products.

Basically, I just went through the store, picked up

samples off the shelf that were canned and

pasteurized products, and this was a quick

semi-quantitative determination. We weren't as

determined that we had to have exact numbers, but

rather an order of magnitude because we were just

trying to say was the radiation going to

significantly increase the amount of furan that

would be present in the total diet at that time.

However, as we got further into this

project, we began to realize that there was a large

number of foods for which furan was present and in

substantial amounts, and it became clear that we

needed to look at it further, as well as needed to

know the quantitative numbers that were there, not

just from a qualitative standpoint.

So, we modified our procedure. In order

to do this, we were using static, headspace

sampling with gas chromatograph determination with

mass spec detection. Our quantitation was based on

stable isotope dilution, as well as standard

addition with known amounts of furan to each food

product.

It is important to note that we were doing

it on each food product because each food product

had a different partitioning coefficient of the

furan between the headspace and the sample.

This method has been peer verified within

our lab group itself by three different scientists,

as I mentioned earlier, and we are currently

participating in a round robin study of the method.

Basically, what we did was we took for

what I call liquid samples, we took 10 grams of the

sample from the food container and placed it into a

headspace vial. For solids and semi-solids, we

took 5 grams of the sample, added 5 grams of water

in the headspace vial. The headspace vial was then

sealed and analyzed.

For some products, it was necessary to

homogenize the sample, and for those products they

were homogenized on ice either using a blender or a

tissue homogenizer. After the samples were sealed

upon the addition of either D4 furan or furan if

necessary. They were vortexed to ensure adequate

mixing of the samples.

It was important to make sure that we did

have adequate mixing because we noted that when we

did not, we retained rather spurious results, but

upon proper control of our samples with proper

mixing and everything, we were able to obtain

extremely good quantitation.

For our studies, we listed limits of

quantitation on the data tables that were presented

on the web. We used rather conservative estimates

of those limits, and for liquid samples, we

determined that was about 2 ng/g, and for solids,

it was about 5 ng/g.

Like I said, these values are fairly

conservative, however, we know that our limits of

detection are much lower than that. For liquid

samples, we estimate those to be about 0.7 parts

per billion, and for the solid matrices, about 1.5

parts per billion.

As Dr. Beru mentioned earlier, we selected

foods based on that initial survey that we were

doing during our radiation studies, as well as from

the literature reports of foods that were known to

contain furan, and using the FDA database to

determine which ones were higher consumption foods.

For each food analyzed, we analyzed from

either two or three brands, and usually from two

different lots per brand. Using this data, we

undertook a systematic manner to obtain

quantitative data.

I am going to go through classes of some

of the foods that we looked at. From the infant

formulas, we looked at powders, concentrates, and

what are called ready to feed foods. The

concentrates and powders were prepared according to

label directions, placed in the vials and analyzed.

The ready to feed, of course, are already ready to

feed, so they were just simply transferred into the

vials.

You can see that we have a range for the

powders of non-detected to 2 parts per billion, for

concentrates of non-detected to 15, and for the

ready to feed, non-detected to 13.

For the powder and concentrate, they are

based on what would have been consumed.

The ranges I am listing here is because

you still see in the next presentation on the

exposure estimates, the range is what is used for

doing that calculation.

For some of the baby foods that we have

analyzed, you can see the apple juice range from 2

to 8, and you can go on down the list up to the

sweet potatoes and garden vegetables, which were up

to 100 part per billion. Again, you can see that

we do have a fairly large range. Again, the garden

vegetables, we are talking about three

manufacturers and two lots per sample.

For some of the adult foods, we have done

a lot more work. You can see that we range from

bread, where it is non-detected to below our

quantitation level. When we have less than 2

there, that means we can detect it, but it was

below our quantitation level, and in the cases of

the tuna and the canned meats, we listed as less

than 5. That means it was within our detection

limits, but below our quantitation level again.

Again, you can see the spread of the

numbers that we are seeing and the various

different types of products that we have been able

to analyze so far. Just so you don't think it is

all so bad, from our original survey, we do know

that many foods do not contain furan, some of those

listed here, and you will notice that man of these

foods are fairly high consumption products, such as

milk and margarine and yogurt nowadays type of

thing. We also included pasteurized eggs and

potato chips in our original survey, as well.

I was asked the question about the heating

the products. We haven't gotten to the point yet

where we are actually cooking unprocessed foods to

look at that, but it is something we do intend to

do eventually, but what we did look at was what

about the foods from the can and if you heat them.

For the foods we looked at here, a very

limited preliminary study, we did chicken broth,

two different pastas, and the infant food sweet

potatoes. The pasta No. 2 and the sweet potatoes

were only treated one way, that is why there is no

second bar there, but you can see from the pasta

sauces and the sweet potatoes, there is not what I

call a significant change upon heating, whereas,

with chicken broth where you basically have water,

and not much lipids or proteins to be holding back

the furan, it does substantially decrease.

So, depending upon what the food would be,

you would either lose the furan or not, and this

gives us a little bit of idea that we may have less

furan actually in the consumption than what would

actually be in the food as we are opening up the

jars.

For the heated samples, they were heated

basically on a hot plate in an open environment

until they boiled for about 10 minutes. In the

microwave, they were heated to boiling, usually for

about a minute for the chicken and pasta. The

sweet potatoes, they were heated what I call until

they were tepid, similar to what a consumer would

have done.

What is ongoing? We are obviously

analyzing more foods. This was set as just a

preliminary survey so far, we are doing a lot more.

We are now looking at foods based on using the USDA

consumption database to say what are some of the

other high use foods that we should go ahead and

analyze that we haven't already done before.

Again, still looking at foods that have

been reported in the literature that contain furan

for which no quantitation is available in the

literature. It should be noted that in most

literature they would state that they found furan,

but would not state what the amount was, they

didn't quantitate the amount there.

Of course, we are going to continue to

investigate the effects of heating on the

concentrations of furan.

For those who would like to see the full

tables, of course, the entire method that we used

is available on the web site as was stated earlier,

as well as all the foods that have been analyzed.

Thank you.

DR. MILLER: Questions?

DR. ARCHER: A question, just curiosity.

What do you make of the potato chip data?

DR. MOREHOUSE: There was no furan in

potato chips.

DR. ARCHER: Any hypotheses?

DR. MOREHOUSE: Nope. Again, you are hear

later on some of the mechanisms, and some foods

that we saw high amounts of furan in, we look at

some of the mechanisms that have been proposed for

where furan is coming from, and they don't

correlate with the products, so obviously, there is

multiple mechanisms, multiple pathways, and potato

chips was one of the things that we thought would

contain furan, and did not.

DR. DOWNER: Thank you very much.

It seems to me that the higher fat foods

tended not to have furan detected. I want to ask a

little bit about the milk, though. Were you able

to look at fat-free milk, 1 percent, 2 percent,

regular milk to see if there were any detectable

differences in those grades of fat content in the

milk with respect to furan?

DR. MOREHOUSE: That was back from the

survey work, and I believe all we did was whole

milk, and we didn't see any furan in the whole

milk, so we didn't bother with looking at any of

the others. We figured if it wasn't in whole milk,

why would it be in the others.

DR. MILLER: Dr. Waslien.

DR. WASLIEN: I was particularly concerned

with the furan content of formula, maybe

non-detectable, the 13 sounds low when you are

looking at a gram quantity, but if an infant

consumes a liter a day, you are up there in the

levels.

I went and looked at the l.d., the least

dose for mice or rats, and the calculated based on

that, of course, we don't have any data for doses

for humans, would indicate that the amount of furan

taken in is 13, and the dose that is least

detectable or least risk is something like 12, so

you are getting close for some of those infant

formulas.

Now, my calculation might be wrong, I just

sat and did it right now, and we are encouraging

infants to drink less than a liter of milk a day,

but it is a concern, and that was my major worry.

DR. MILLER: That's true, but the issue

that we are concerned with here is what work would

we suggest to the agency in order to get enough

data in order to be able to come to that

conclusion.

DR. WASLIEN: Well, partly I would think

one of the things you might want to look at is

age-related differences in metabolism since a

newborn infant has all kinds of other metabolic

differences.

DR. MILLER: Hold that thought.

DR. WASLIEN: Okay.

DR. MILLER: Dr. Chesney.

DR. CHESNEY: I also have many, many

thoughts as you do, but for the moment, I wondered

if you could clarify the infant formula slide for

me. I didn't quite understand

non-detectable-2-15-13, and you also said based on

consumed, and I may have heard wrong. I wanted to

be sure I understood the slide.

DR. MOREHOUSE: The slide, that is the

range that we found for the products that we have

analyzed. From non-detectable to 2 for the powers,

from non-detectable to 13 for the concentrates, I

think it was, and the powders and concentrates are

based on as it would have been prepared by the

consumer for consumption.

In other words, we took the powder and

made up the solution was it was by label, so it is

based on the prepared formula, not the powder

itself.

DR. CHESNEY: I understand. Thank you.

DR. MILLER: Dr. Chin.

DR. CHIN: Going back to your table or

figure that showed the effect of cooking on furan

levels in various foods, there were I guess a

couple of bars where either the value was zero or

there were no values.

DR. MOREHOUSE: Those were because for the

second pasta sauce and for the baby food, we did

not do the second treatment, so the pasta sauce No.

2 was only heated, and the baby food was only

microwaved.

DR. CHIN: Thank you.

DR. MILLER: Dr. Aller.

DR. ALLER: A question again on the infant

formula. I know you mixed that. Was it heated

also?

DR. MOREHOUSE: No, just mixed.

DR. DWYER: Just a question. Could you

explain the difference between limit of

quantitation and limit of detection? It is just

that you can't above the limit of detection, you

can't quantify until you get to 2 parts per

billion, is that right?

DR. MOREHOUSE: Right. Because of the

mass spectroscopy's sensitivity, we can detect it

or we put very stringent requirements on

quantitation right now because the method has not

been totally peer verified, we felt that we didn't

want to say that we could do 1 part per billion,

even though we can see it, but we don't want to

take the quantitation level there yet.

DR. MILLER: Thank you.

The next speaker is Mr. Jeremy Mihalov,

FDA, will talk about exposures.

Exposure

MR. MIHALOV: My name is Jeremy Mihalov,

Office of Food Additive Safety. This also was done

with Dr. Michael DiNovi. I am going to give you an

overview of our exposure assessment for furan from

the consumption of adult and baby foods.

I will start off, give you an idea for the

model that we used to estimate exposure, and this

is fairly similar to most exposure assessments,

simply that the total exposure for a person to

furan is the sum of the exposures from each food,

overall foods that contain furan, and exposure from

each of those foods is simply the product of the

intake of that food modified by the concentration

of furan modified by the concentration of furan in

that food.

We looked at adult foods, baby foods and

also the infant formula, and they were considered

separately.

The sources of our data. For intake data,

we used the USDA 1994 to 1996 and 1998 USDA

Continuing Survey of Food Intake by individuals.

This was a two-day survey, two nonconsecutive days.

For each of the years, there was about 5,000

people, so we have data for basically 15,000

individuals, and we know what they ate and how much

for each of those days.

We then looked at the furan concentration

data which you just heard about, and we looked at

those lists of foods, and looked at the survey

data, how much of those foods did those people eat

multiplied by the concentrations, and you can get

an exposure for each individual.

This may be somewhat of an iteration of

what you have already heard. By looking at the

infant foods, we group them into juices, fruit

purees, vegetables, mixed chicken meals, had a

separate for infant formula.

For the adult foods, we grouped them into

brewed coffee, instant coffee, broths, soups that

contain meats, spaghetti sauces, chili, pasta,

ravioli--they were both canned--juices, pork and

beans, canned string beans, canned tuna, canned

corn.

Just to go over some of the levels again,

within each food type, the ones I just listed,

within the food types, there wasn't a lot of

variability. Overall, the range, looking at all

the food types, went from limited detection up to

about 125 mcg/kg.

Specifically, looking at the infant food

groups, the highest were the sweet potatoes and the

garden vegetables, juices were generally low, below

10 mcg/kg. The fruits and mixed meals were below

30. Other vegetables ranged between 30 and 60.

With the formula samples, about half were below

limit of detection, and we used the mean, which was

about 7 mcg/kg.

With the adult foods, the coffee had the

greatest variability, between limit of detection up

to 80. The juices, tuna, broth, sauces were all

generally low, below 15. The soups and the pork

and beans had a fairly wide variation, the soups

being the highest. The chili, beef ravioli, and

spaghetti, the canned pastas were between 30 and

100.

Going back to discussing the model,

generally, when you do an exposure assessment,

there is a certain amount of uncertainty, and we

compensate the uncertainty with making certain

assumptions. Whenever we make an assumption, we

tend to make it conservative, and this is typical

for agency exposure assessments.

The first assumption is that the

concentration of furan and all the furan-containing

foods will be at the mean within the food type, and

as I said there is generally little variability

within the food types, so we use the mean. When we

are looking at chronic exposure, that is generally

how we do it.

Second assumption, for all foods within a

food type that are shown to contain furan, we

assume that it does contain furan. In other words,

they have seen it in canned chili, so when we did

the exposure assessment, we assume anytime anybody

eats chili, it also contains furan, and as there is

more data collected in the future, those

uncertainties could be reduced.

The last assumption is that the two-day

survey intake data that we used reflects a lifetime

exposure.

So, getting to the final numbers, we used

the published April 20th concentration data that is

on the internet. Using that, for the adult foods

for people ages 2 and older, that ate those foods,

the mean consumption was 0.3 mcg/kg-body

weight/day.

The 90th percentile, which is what we

consider to be the heavy consumer, on the upper end

of the distribution, is at 0.6 mcg/kg/day.

When we looked at the infant foods, and

these are age 1 or less, that ate those foods, the

mean was 0.4 mcg/kg/body weight, and the 90th

percentile was 1 mcg/kg.

We ran the exposure assessment looking at

the individual foods just to get a sort of profile

of how those different food types contribute to

that overall mean, and this is just a table of how

those foods contribute, coffee being the highest

out of the groups that were tested, going down to

broths being negligible.

For the infant formula, we took a slight

different approach, a more simple approach. There

is sort of standard numbers for infant formula. In

order for an infant to thrive, they need to consume

between 100 and 120 kilocalories per kilogram per

day, and infant formula is usually formulated to

contain 0.8 Kcal/gram when it is prepared, and I

used the mean furan concentration of 7 mcg/kg, and

if you do the arithmetic, you can come out at a

mean exposure of 0.9 mcg/kg/day for an infant

consuming infant formula at the level needed to

grow.

To sort of sum up overall, the variability

of the furan levels within a food type is generally

small, so we can pretty much assume that additional

measurements within food types won't have much

effect on the overall exposure, however, because

the number of food types that have been tested is

generally limited, additional measurements in other

types of foods could have an overall effect on the

exposure, especially with foods that are consumed

in high quantities or also foods that have high

concentrations could affect the exposure.

Thank you.

DR. MILLER: Dr. Waslien.

DR. WASLIEN: I did a quick recalculation

of my numbers, and I am off by 1,000, so I skipped

nanograms in there. I just wanted to make that

correction.

But even so, I think when you look at

infant formula, I hesitate to take the mean of

values, because the likelihood of a person changing

from one formula to another is not that high, so I

think you are looking at the individual risk from

formula, so the child who is consuming a formula

with 13, if it is a ready to consume formula, is

probably going to be consuming that reasonably

every day.

DR. NELSON: I guess a similar question.

On the other food products, did you use the mean in

your conservative estimate, or did you use the

highest value?

MR. MIHALOV: We used the mean of all the

concentrations for all the food types. Generally,

when you are looking at a lifetime exposure, you

can pretty much assume that if there is a

distribution over time as you consume that food,

one day you might consume the minimum, the next day

you may consume the max, but over the course of

time, you are going to consume at the mean.

Of course, if there is additional data to

demonstrate that there is some reason to why there

is a distribution, you know, that could change, but

generally, for now we use the mean.

DR. RUSSELL: Just a question of

information. With so many adult Americans eating

out, particularly in fast food type restaurants, do

you have any data on fast foods that have been

prepared under high heat conditions?

MR. MIHALOV: Well, the survey data

includes restaurants and home cooking. It is

essentially the survey is given out and whatever

was eaten by those individuals on those two days,

that is what they report.

DR. RUSSELL: But in your analysis of

foods that FDA has analyzed, how many foods come

from that type of an environment that were analyzed

actually? I noticed a lot of canned and jarred

things, very important for infants particularly,

but I was just concerned about the adult exposure.

MR. MIHALOV: Just looking at the list, I

would say a few of them are probably restaurant.

Like I had said, if they found it in a food, we

assume that it is in all foods of that type, so,

for instance, the chili was a canned chili, but we

assume that all chili contained furan when we did

the exposure assessment, so if they had chili at a

restaurant or if they made it at home, that was

taken into account. If there is further data to

show that canned is higher than home-cooked or

restaurant, then, we can make that change.

DR. MILLER: Dr. Lee.

DR. LEE: To continue that thread, I

assume that there is a fair amount of looking at

canned and jarred foods because the furan is fairly

volatile, so the packaging method itself keeps the

furan present in the food, is that a fair

assumption?

MR. MIHALOV: I couldn't say.

DR. MILLER: Dr. Nelson.

DR. NELSON: That would fit with the

infant formula data because the powdered stuff is

typically spray dried where you have a lot of

opportunity for dissipation of furan as opposed to

the canned concentrate or ready to drink formula.

DR. MILLER: Do you want to respond to

that?

DR. LEE: I just want to continue along

that line of thinking. Have you ever considered or

does anyone have any data on animal exposure,

particularly pets consumption, because you

basically have a pretty monotonous diet, and there

are pet foods that do come in cans, so one would

expect that there would be a fairly good exposure

there that you can model, is there any interest in

looking at that?

MR. MIHALOV: That could probably be done

if we had concentration data. I am sure that there

is some information on how much food a typical

animal eats per day, but it would be pretty much as

simple as that, because a pet would consume one can

or two cans, or something along those lines, but

that could be one.

DR. MILLER: Dr. Chin.

DR. CHIN: I just wanted to comment a

little bit on the thought about foods purchased at

restaurants. I think one of the other

considerations in terms of foods that are purchased

at restaurants is that not only do you consumer the

food at the restaurant, but there are situations

where you have takeout food and you take it home.

You might reheat it in the microwave. We

have seen some limited data where you take a food

from a restaurant, put it in the microwave, and

under those circumstances, at home, you would

produce some more furan.

DR. MILLER: Dr. Dwyer.

DR. DWYER: Just a question about the

exposure assessment. I am a nutritionist and so

when we use these kind of data, we use the Iowa

State method for adjusting the nutrients to pull in

the tails of the distribution.

Do you do that in exposure assessments, as

well? In other words, you have two days worth of

data, and so you are able to get an estimate of

usual intake from that, and I wondered if you

adjust for that. The effect would be to change the

exposure, i believe.

MR. MIHALOV: It doesn't sound familiar.

Basically, we take the distribution of all the

consumers and pull a mean in 90th percentile right

from the distribution, but not adjusting it.

DR. MILLER: Dr. McBride.

DR. McBRIDE: In answer to Dr. Nelson's

point, I looked at that data of the prepared

formula and the powdered formula and thought maybe

it was a difference in processing, might be heating

it more when it is packaged in liquid form.

I also did the calculations for the worst

case scenario because that is something I think you

were getting at, and if you have a chubby

8-month-old who consumes a liter of formula and 5

jar of sweet potatoes a day, I assumed it had to be

at least 8 kilos to do that, I got a worst case

scenario of 8 mcg/kg.

DR. MILLER: How much?

DR. McBRIDE: Eight.

DR. MILLER: Dr. Chesney.

DR. CHESNEY: Not why I am here, but the

fast food issue is intriguing. I wonder if the

packaging contains furan. Most fast food, you get

plastic containers to put it in, and most people

reheat it in the container. Just a thought.

DR. MILLER: Any more comments? If not,

thank you.

The next speaker is Dr. Don Forsyth from

Health Canada, who will take about the formation of

furans.

Formation

DR. FORSYTH: First of all, I would like

to thank the committee for the invitation to appear

here today on behalf of Health Canada.

My name is Don Forsyth. I am a research

scientist with the Food Research Division of the

Bureau of Chemical Safety with Health Canada in

Ottawa.

I would like to take you through the

background as far as Health Canada is concerned on

this issue. In late March 2004, we became aware of

U.S. FDA's investigation of furan in canned and

bottle food commodities. Upon learning that furan

has been shown to be carcinogenic in rodent models

and has been classified as possibly carcinogenic to

humans, we commenced method development as of April

of this year for support of the study of mechanisms

of formation, as well as a preliminary survey of

Canadian food products.

Although furan is used in industrial

processes, as has been discussed this afternoon, we

considered that the likely source would be

formation during food processing during the initial

start-up of our investigations.

One thing we should mention about furans

in foods, however, is that furan derivatives not

only have been reported in a wide variety of foods

previously, but they are also a significant flavor

and odor component in coffee, cocoa, and various

cooked meat products.

So, these are products or compounds, I

should say, which arise naturally during the

processing and cooking of various food commodities.

Furan itself, the parent compound, has

been previously isolated in coffee, canned beef,

sodium caseinate, soy and rapeseed protein, as well

as caramel.

Looking through the literature, you can

find a variety of possibilities or comments from

previous authors working in flavor and odor studies

about how these compounds are formed.

The three that we chose to look are the

thermal degradation of carbohydrates or the

Maillard reaction, thermal oxidation of lipid, and

decomposition of ascorbic acid and its derivatives.

Just to take a look at an older study

conducted by Persson and von Sydow back in 1974,

one of the first studies that you find where they

are able to determine that certain components in a

processed food could increase the levels of furan

produced within that food commodity under typical

canning conditions.

Using a beef, water, and sodium chloride

formulation fairly typical of the day for canned

beef products, they found that even with just these

basic components, there was fairly large levels of

furan produced, however, with the addition of the

fat, as you see in the second formulation shown

here, the levels increased dramatically above the

formulation without the fat.

Then, when they looked at the formulation

with a small amount of carbohydrate added, they

found essentially no increase over the basic

formulation of beef, water, and sodium chloride,

and then finally with the fourth different

formulation shown here, with the fat and the

carbohydrate added in addition to the other

constituents, you get levels similar to the beef,

fat, water, and sodium chloride formulation.

So, in this particular study, the authors

determined that the fat was a precursor for the

formation of the furan.

Briefly looking at our own analytical

methods that we developed to support these studies,

one was a headspace analysis which we used for the

mechanisms of formation and for the food survey,

and also the microextraction technique, which is a

SPME related method developed at Health Canada

which we applied to the food survey results, which

we will be showing later on in this presentation.

Both methods are based on isotope dilution

using a d4 furan surrogate, measurement by gas

chromatography/mass spectroscopy.

Formation studies. We took some of the

test compound or precursor to a small vial

containing 0.5 ml of water. The vials were then

heated for 30 minutes at 118 degrees, conditions

not too dissimilar to commercial canning

procedures, allowed to cool, and then force cooled

to 4 degrees when the D4 furan surrogate was added,

so that we could analyze the resulting anilides

which may have formed during this study.

The first table is on the level of furan

which were formed with the addition of ascorbic

acid and ascorbic acid derivatives. Virtually all

of these compounds are commercial antioxidants

which are used in foods, and you can see that the

ascorbic acid with or without the iron present,

iron is a known promotor of oxidation and

therefore, would be expected to, at least in some

cases, increase the amount of furan which would be

produced.

The sodium ascorbate, again relatively low

levels. The dehydroascorbic acid, however, with

either the iron present or absent gave higher

levels, almost 10 times higher than the ascorbic

acid.

Isoascorbic acid, again similar in this

case to the dehydroascorbic acid, and the sodium

isoascorbate in the presence of the ferric iron

produced almost again 10 times as much as the

sodium isoascorbate by itself, but again, both half

the levels that we found with the addition of

dehydroascorbic acid.

Finally, the ascorbyl palmitate compound

produced fairly low levels of furan as well.

Then, when we looked at fatty acids and

oils, we found that the degree of unsaturation in

the compound had an effect with an increase in the

levels of furan formed increasing as you go from

linoleic up to the linolenic with an increase of

about 4 times in this case.

Now, in these two fatty acid series, we

did see an increase in the production of furan with

the addition of the ferric iron, and in the case of

the oils, what you see in the last four rows of the

table, again, a similar increase as you go from the

trilinoleate up to the trilinolenate, approximately

again roughly 4 times.

In this particular case, with the oils,

the ferric iron had an increase in the production

of the furan for the trilinoleate, but not for the

trilinolenate.

Comparisons were made between the reaction

products and the furan standard, and as you can see

in this particular case, the comparison between the

linolenic acid reaction mixture and the furan

standard, you get a very similar pattern both for

the total iron chromatogram as well as the

fragmentation pattern for these two.

So, what we have determined so far is that

at least in the model systems that we have tested

so far, we found that the polyunsaturated fatty

acids, such as the linoleic and the linolenic, did

produce furans likely through a free radical

formation mechanism with ring closure resulting in

the formation of the furan, and also decomposition

of ascorbic acid derivatives particularly the

dehydroascorbic acid and the isoascorbic acid also

led to the formation of furan.

Some of our survey results in baby foods.

Here, we have a comparison between our two

methodologies, the microextraction technique in the

first column, and the static headspace in the

second.

Levels varied as low as 6 parts per

billion, and went as high as approximately 154

parts per billion in the mixed vegetable. Each one

of these values that you see is the average of two

individual analytical determination for each

method.

When you look at adult foods, we found

that the chili products had the highest levels

amongst those that we analyzed with levels ranging

up to as high 227, 236 depending upon the method

value, as well as 152, soups there was a broader

range ranging from as low as 35 ppb up to

approximately 115, 117 ppb.

We have looked at one stew product so far

with a value of approximately 80 parts per billion,

one bean product with relatively low value, 14

parts per billion.

The luncheon meats that we looked, I

believe were both beef or pork based, and they were

all relatively low with levels down to 4 parts per

billion, and no higher than approximately 30 parts

per billion.

Fresh brewed coffee, as would be typically

served, would range between 14 to approximately 50

parts per billion.

Next steps for our work at Health Canada

include further studies on the mechanisms of

formation using additional model systems, as well

as precursor fortified food matrices.

Examining losses of furan during food

processing and cooking operations, as well as

further examinations of canned and bottled

products. We also have a round robin method

validation study to complete, and that is ongoing

as we speak, and we should be reporting back on

that in just a few weeks.

Then, finally, to continue updating our

health risk assessment as new data becomes

available.

With that, I would just like to thank

everyone for their kind attention.

DR. MILLER: Thank you.

Any comments or questions?

Questions of Clarification

DR. ACHOLONU: I was wondering, is it

advisable to check the concentration of furan in

mixed vegetables? Could you justify using that?

Mixed vegetables, which has different kinds of

vegetables put together, what do you do?

DR. FORSYTH: The premise of that, of

course, is for health risk assessment, in which

case we are interested in consumption of food

commodities that are related to a typical diet, so

this is one particular food product that we

happened to analyze, and that is essentially the

extent of our interest in it at that point.

DR. ACHOLONU: But does it have any

scientific basis?

DR. FORSYTH: It has a scientific basis in

the sense that with that particular food matrix,

those are the levels that you are reaching. It

also brings to mind what is causing that formation,

which is something that we are certainly interested

in, because it doesn't fit into the existing models

that we have pursued so far. So, yes, I think it

has a lot of scientific interest.

DR. MILLER: Dr. Krinsky.

DR. KRINSKY: Could you just describe the

conditions for generating the furan from the

linolenic acid? Was this heated, cooked, baked, or

was it just linolenic acid out of a jar?

DR. FORSYTH: I didn't actually conduct

this study myself. My understanding is that the

compound, which I believe was 10 mg of the

precursor would have been added to the vial

containing 0.5 ml of water, and then that would

have been heated to the 118 degrees for 30 minutes.

DR. KRINSKY: Thank you.

DR. MILLER: Dr. Lund.

DR. LUND: Looking at the Persson and von

Sydow data, I wondered if you have had any comments

with regard to the degradation of furan upon

prolonged heating. Some of their data, at least on

the surface, would suggest that upon prolonged

heating, you probably get formation rates equal to

degradation rates because the concentration is not

changing.

DR. FORSYTH: First of all, I am not sure

if that is what they were alluding to or not. I

thought that data was to look at probably losses of

furan due to revolatilization during heating and

processing in the kitchen.

I know that there is some concern that you

may actually be creating more furan with

post-processing sample manipulation, but I don't

know if anybody has actually really looked at that

yet.

DR. MILLER: Dr. Callery.

DR. CALLERY: We addressed part of this

already, but it's an impressive amount of work that

you have done since March. I have been looking at

this, and I admire you for being able to get so

much data so rapidly. I have a couple of little

questions, though.

The ascorbic acid one in particular, from

what I remember the structure of ascorbic acid,

it's a highly oxidized species and it gets even

more oxidized readily, and that you are actually

asking iron to participate in this reaction to

facilitate an oxidation.

I think the point I am trying to make is

that the furan is more like a reduction or

elimination of water, a couple water molecules, and

more a reduction. If you looked at the oxidation

states of the various carbons, they are not at a

higher oxidation state than ascorbic acid.

So, it may be something very different

going on here that is involving the metal in the

process of making furan, if that is what you are

actually doing. I think the question was also the

yield that you are addressing here, maybe there is

10 mg of ascorbic acid or I am sure 10 mg of fat,

but that nanograms per gram is incredibly small

yield in the process of cooking, so I am wondering

a little about that, too, if you aren't just making

some furan this way out of this particular

compound.

DR. FORSYTH: I have no doubt that the

yields, particularly with the ascorbic acid tend to

be quite low, but typically, levels used in food

are reasonably high, and this wouldn't necessarily

be the only way that furan would be formed, and it,

of course, had been alluded to earlier by one of

the other speakers, that we undoubtedly will find

that there is multiple pathways contributing to the

overall levels of furan present in the food.

These are, I can't stress strongly enough,

preliminary investigations into possible means that

furan could be formed. There had been previous

work with some of the ascorbic acid related

derivatives that had indicated that a variety of

furans were formed during thermal degradation, and

this is what we were attempting to follow up on

with this study.

DR. MILLER: Dr. Chin.

DR. CHIN: I would also like to compliment

you on doing such an impressive amount of work in

such a short period of time.

Just a question in terms of your thoughts

on other possible precursors. Are you planning to

look at the possibility that perhaps carotenoids

and similar types of materials might be a precursor

also?

DR. FORSYTH: Our immediate plans, and we

are doing this as we speak, looking at Meyer type

reactions at present.

DR. CHIN: Just a follow-up, and the

reason I am asking is because in products like the

sweet potatoes where there are amount of furan have

been detected, I mean those materials are high in

carotenoids, whereas, they are generally low in

fat, and I don't think the ascorbic acid levels are

particularly high, so just a possibility in terms

of another possible precursor.

DR. FORSYTH: It sounds like we will be

following up with you shortly.

DR. MILLER: Dr. Dwyer.

DR. DWYER: Just a question more from

ignorance than anything else. Are the methods that

you are using in Health Canada and the Food and

Drug Administration's methods the same? I just

looked at chili, and it looked like the Canadian

chili was much more potent than the American chili,

and just wondered if there were some way if they

are not the same method, if there is some way to

get some comparable methods in both countries or to

divide up the work and do some round robin studies,

so that we are not overduplicating things that are

basically the same trading area.

DR. FORSYTH: Round robin testing is

underway. In our own case, it was set aside

because we were concerned with what levels were

present in the Canadian food supply, so that was

our first priority. Now that that is completed, we

do have the two methods which we wish to compare,

not only against FDA's method, but also any

industry methods which are out there, and we will

be doing that through the round robin study.

DR. MILLER: Dr. Russell.

DR. RUSSELL: Yes. Following up to Dr.

Chin, I also had wondered about the sweet potato,

but I was wondering if the soup, it says soups in

both the FDA data and your data, I was wondering if

there was any clues that could be gotten with the

types of soups.

There was a three- or four-fold variation.

What types of soups were looked at?

DR. FORSYTH: I believe there was--I hope

there was a listing of the actual products that we

tested included in your information package. In

any case, we have tested 30 products so far. We

hope to be testing more in the near future but for

the time being, we will be participating in the

round robin study first.

DR. MILLER: Dr. Chesney.

DR. CHESNEY: Again, just for

clarification, and this may seem like a very

simplistic question, but is it correct that the

furan is created by oxidation of the ascorbic acid

products and the polyunsaturated fatty acids, it's

a product of oxidation of those entities, am I

correct?

DR. FORSYTH: I think with the ascorbic

acid, I would view it more as a thermal degradation

as opposed to an oxidation per se, whereas, with

the lipids, it is a radical-mediated oxidation

mechanism, yes.

DR. MILLER: Dr. Nelson.

DR. NELSON: Following up on Dr. Dwyer's

comment about the equivalence of method or

recognition of each other's method, I guess, would

the food supplies be considered equivalent enough

for us to sort of accelerate the database by again

sharing the activity? I don't know if we need the

same trading area, we have to have a NAFTA

database.

DR. FORSYTH: Is that related to me?

Presumably, in Canada, we find that we have

different branding as opposed to U.S. foods, but in

cases where you have the same manufacturer, I

personally can't see any reason why the data

couldn't be used.

DR. MILLER: Dr. Downer.

DR. DOWNER: I just wanted to respond to

Johanna's question about the chili. I think in

Canada, they may be using Spam from looking at the

database here, so maybe that is where the

difference is.

Thanks for a good presentation. I am just

wondering about Dr. Morehouse's presentation when

he looked at no furan detected in some of the

different groups of foods, particularly foods from

animal sources. I was thinking that perhaps

because it was a bit lower in fat.

But on one of your slides, when you talked

about the effect of canned beef formation and you

added fats, it was really the opposite. Could you

talk a little bit about perhaps the differences

that were seen there?

DR. FORSYTH: Actually, in retrospect,

when you look at their study versus our own results

on canned luncheon meats, I have concerns. It was

a 1974 survey, well, different analytical

capabilities than we have now, so I believe that

that work does bear out the results that we were

finding in terms of the presence of fat promoting

the increase in furans.

However, I can't reconcile the findings

that they reported in that publication with our own

and also with FDA's current findings on luncheon

meats, which I would have felt should be

comparable.

DR. MILLER: Dr. Dwyer.

DR. DWYER: Just a question again about

methods. Is there a standard method, or are you

driving toward a standard method instead of

everybody having their own method especially in

North America, it seems like this might be

something to agree about one way or another?

DR. FORSYTH: There has been a few

factors, time being one of the largest.

Essentially, with the time constraints that all of

the organizations have had, you basically begin

with the people that you have who know how to do

these types of analyses, and you ask them to come

up with a working method, and I believe that is

essentially what has happened here.

The next phase will be these organizations

to have, and this is being done as we speak, a

round robin study in which case we all examine the

same food commodities and see if we get, hopefully,

roughly the same answers. Depending upon the

results of that study, there would then be either

adjustments made or discussions amongst the various

organizations to determine why, if there are indeed

any, there are differences in our results on these

particular food commodities.

DR. MILLER: Why don't we move on. Thank

you very much.

The next speaker is Dr. Glenda Moser. You

have got 25 minutes.

Scientific Overview of Furan in Foods

DR. MOSER: Thank you.

Well, I would like to begin by thanking

the committee for inviting me today and say that my

talk is going to be a little different than those

that have been presented up until this point, and,

in particular, I am going to be talking about some

in-life studies that we did to try and determine as

best we could a mechanism for furan-induced liver

tumors in mice.

In a two-year NTP bioassay, there were

both non-neoplastic and neoplastic findings in rats

and mice of both sexes. In particular, there were

neoplasms, cancer, in the liver in the rats, and

cholangiocarcinomas in the rats, as well as

mononuclear cell leukemia.

The important thing here is that at 2

mg/kg, there was approximately a 90 percent

incidence of cholangios. In mice, there was an

increased incidence of benign tumors of the adrenal

gland, as well as hepatocellular tumors at both 8

at 15 mg/kg.

Here, what you see is more of what I am

going to be talking about today, is the incidence

of your hepatocellular adenomas or your benign

tumors, hepatocellular carcinomas, and then the

adenomas and the carcinomas together in female mice

and in male mice, and you see a dose-dependent

increase in both the males and the females.

Another important factor for the study

that I am going to be talking about is the

incidence of spontaneous liver tumors in both male

and female mice. Historically, in your B6C3F1

mice, you will have somewhere between 20 and 60

percent incidence of liver tumors in control

animals. Usually, it's much lower in your female

mice. It is for that reason that we conducted our

two-year study in female mice.

Sometimes it is difficult when you have 40

or 50 percent incidence of spontaneous liver tumors

to find an increase in male mice.

Cancer, as we are well aware, is a highly

complex, multistage process that is operationally

divided into three stages, namely, initiation,

promotion, and progression. Initiators or

genotoxic agents directly damage DNA. They change

the primary sequence of the DNA.

Genotoxic agents can be carcinogenic after

a single exposure, and, in general, it is found

that genotoxic agents are better carcinogens if

they also induce cell proliferation, so they can

fix those mutations.

Metabolism, there are many carcinogens,

not only liver carcinogens, but carcinogens in

other systems, the parent compound is not

carcinogenic, but it is metabolized or intoxicated

to its toxic moiety.

In the case of furan, you have the

cytochrome 2E1 in the liver that metabolizes the

furan to its toxic moiety. There are a variety of

mechanisms of genotoxicity which we are not going

to talk about today.

What we have here is somewhat of a summary

of assays for genotoxicity after furan exposure.

We have those that are negative, those that are

positive, those that are highlighted in mammalian

systems, and those that aren't, are either in your

Salmonella or your Drosophila.

In spite of the fact that there are some

positive tests for genotoxicity, furan is generally

considered to be non-genotoxic. Non-genotoxic or

epigenetic agents, they are generally believed to

clonally expand those initiated cells.

They provide an environment in which those

particular cells opportunistically grow and expand,

that, in general, your non-genotoxic agents require

multiple exposures, sometimes over the course of

the entire life span of the animal, and generally,

with your tumor-promoting agents or your

non-genotoxic agents, it requires high doses.

In the early stages, tumor promotion is

generally reversible, so that in a 13-week study

with furan, the animals were dosed at 8 and 15 mg,

then, they were held for either 6 months, 9 months,

or 15 months, and 18 months, and evaluated.

In these particular studies, furan was not

reversible, particularly the cholangiocarcinomas.

It is important for us that B6C3F1 mouse

is the mouse used by the National Toxicology

Program. Part of the reason that it is used is

that it is sensitive to cancer, and that's both

spontaneous cancers, as well as chemically induced.

In particular, the liver, of the 500

compounds that the NTP has evaluated, approximately

50 percent of them are carcinogenic in the mouse

liver. Really, that was the reason that we

conducted these studies was to try and make some

association of what relevance are these mouse liver

tumors to humans.

There are a whole variety of non-genotoxic

mechanisms, we are not going to talk about them

today. The one I do want to talk about is the

cytotoxicity in cell proliferation, that furan, in

short-term studies, is necrotic to liver cells,

hepatocytes. It kills them.

After this, in order for the liver to try

and maintain its homeostasis, we have regenerative

or compensatory cell proliferation. There are

certain hypotheses that believe that the mutations

that you may find in the H-ras gene or some of the

other genes are secondary to this cytotoxicity and

cell proliferation, that the DNA is believed to be

inordinately sensitive to mutation when it is

dividing. It is kind of spread out there, kind of

opening itself up, if you will.

Liver cytotoxicity, how do we determine if

a chemical is cytotoxic for the hepatocytes?

Commonly, that is done by clinical chemistry, by

evaluating serum ALT, alanine aminotransferase, or

sometimes SDH levels, sorbitol dehydrogenase, and

secondly, by histopathology, that liver sections

are stained with hematoxylin and eosin, your H & E

stained section, you will commonly find pycnotic

nuclei that generally the nuclei of the hepatocytes

are blue, and those cells that have been exposed to

a cytotoxic agent, their chromatin and the nucleus

is sometimes so blue that it is almost black.

You will find an inflammatory response.

You have the recruitment of both your mononuclear

and your polymorphonuclears to kind of clean up the

debris as a result of this cytotoxicity, and

thirdly are the degenerated hepatocytes or the

cytoplasmic vacuolization.

We conducted a 13-week study in male

B6C3F1 mice. These animals were exposed by gavage

intergastrically 5 times a week. The dose levels

were 0.5, 2, 4, 8, and 15 mg/kg. We quantified

cell proliferation by BrdU. In these particular

studies, we used an osmotic pump, a 7-day. The

advantage of that is that the liver--the life span

of a hepatocyte in a mouse is generally about 200

days, so at any one point in time, you are only

going to have 0.5 percent of your hepatocytes

dividing.

So, if we go over the course of 7 days,

then, we accumulate all the cells that are divided,

all the cell replication that occurred in those 7

days.

So, this is an H & E stained liver section

of the mouse, and what you see here, you see the

inflammation that is common after exposures to

cytotoxic agents. You have the influx of your

morphonuclear, of your mononuclear and your

polymorphonuclear neutrophils.

After you look at the incidence of liver

cytotoxicity, after 1, 3, 6, and 13 weeks, you will

see that the highest doses, you have a greatly

increased incidence of cytotoxicity, also, at 8

mg/kg you have a significant increase, and at 4,

you have an intermediate response.

Cell proliferation. One of the markers,

the ways of quantifying cell proliferation is the

labeling index that measures the S phase of the

cell cycle. There are a variety of methodologies.

You can look at mitotic figures, quantify those.

You can look at KI67 gene, you can look at PCNA, a

proliferating cellular nuclear antigen that is part

of a quaternary complex.

For us, we used BrdU, bromodeoxyuridine.

It's a thymidine analogue, so when the DNA is

replicating, in place of the thymidine, a certain

percentage of the BrdU will be incorporated.

Then, we have an antibody to the BrdU, so

we immunohistochemically stain for cells that have

incorporated this BrdU. There are a variety of

routes of administration depending upon what the

endogenous cell proliferative rate is. You can use

a pulse. So, for instance, if you are looking at

cell proliferation in the skin, you may inject IP

an hour later euthanize the animals.

For us, there is the cumulative is the

advantage, as I said earlier, because you can find

out the cell proliferation that has occurred over a

period of time.

Quantifying, how do we quantify this?

Well, by light microscopy, we look at these

immunohistochemically stained sections. [Off

microphone.]

I am sorry, excuse me. At the 4 mg/kg,

these are the cells that have incorporated the

BrdU. Over here, at 8, you will see many more of

them. So, what we do is we evaluate 2,000 hepatic

nuclei and determine the percentage for those

nuclei that have incorporated this stain.

In our 13-week study, you will see that we

have a significant increase at the 15 mg/kg at all

three time points, 1, 3, 6, and 13 weeks. At our 8

mg/kg, which I found to be interesting that your

calculations were 8 mcg/kg, you have a significant

increase at 1, 3, and 6 weeks. At 3 weeks, you

also have an increase in 2 and 4.

We also conducted a study in female mice

in which they were exposed to 00.5, 1, 2, 4, and 8

mg/kg, and you will see that the highest dose of 8

mg/kg produced a significant increase in your ALT

levels with an intermediate response in the 4.

The SDH was elevated in both the 4 and the

8 mg/kg. If you looked at the hepatic labeling

index, again, you saw a significant increase in

female mice at the highest dose of 8 mg/kg, and no

other increases.

In light of this data, we conducted a

carcinogenicity study, a two-year study. It was in

female B6C3F1 mice. Our dose levels were 0, 0.5,

1, 2, 4, and 8. Eight, you will recall was the

dose that produced both cytotoxicity and an

increase in labeling index, that we had 50 to 100

animals per group, particularly in our lower groups

we wanted to be able to detect the significant

increase if there was one, so we increased the

number of animals.

They were exposed for two years. They

were exposed by gavage, and this was 5 times per

week.

We conducted necropsies on these animals

after two years, and what you will see here, on the

left, is a normal mouse liver. This was an animal

that was exposed to 8 mg/kg, and at gross necropsy,

you will often find these masses.

We quantified the incidence of these

masses at necropsy. There was a significant

increase, 100 percent of the animals had liver

masses at the final necropsy, and there was also a

significant increase at 4 mg/kg.

We evaluated H & E stained liver sections

for inflammation. As before, you will see that at

your 8 mg/kg, that there was an increased incidence

of livers with both moderate and marked subcapsular

inflammation or cytotoxicity, and there was an

intermediate response at 4 mg/kg.

This is an H & E stained liver section,

and what we have here is a hepatocellular tumor.

It is a metastatic one as it ended up being. You

can see how there is loss, there is disruption of

the normal liver architecture. So, we evaluated H

& E stained sections for the presence of

hepatocellular adenomas, carcinomas, and foci.

You will see at 4 mg/kg, there was a

significant increase in foci. Foci are believed to

be pre-neoplastic liver lesions that have the

ability to progress on to become benign or

malignant liver tumors.

At your 8 mg/kg, you had a significant

increase in the incidence of foci, adenomas, and

carcinomas.

What we say here is that there is a very

good correlation between cytotoxicity as measured

by ALT or SDH, and labeling index, and the

incidence of liver lesions. So, when those, at 8

mg/kg, where you had an increased incidence of

cytotoxicity, you had an increase in labeling

index, you also had an increase of masses at

necropsy, and adenomas and carcinomas

microscopically.

At 4 mg/kg, you had somewhat ambiguous

intermediate responses in the short-term assays,

and you had an increased incidence of lesions or

masses at necropsy, and an increased incidence of

pre-neoplastic lesions by light microscopy.

So, in conclusion, what we can say is that

this study demonstrated a dose-dependent increase

in furan-induced liver tumors in female B6C3F1

mice, and a relationship between the dose,

cytotoxicity, compensatory cell proliferation, and

tumor induction.

An overview. In this particular study, we

have reproduced the results of the NTP bioassay.

In the NTP bioassay, they used 8 and 15 mg/kg.

They had an increased incidence of liver tumors as

did we.

What we noticed here is that there is a

threshold that doses below 4 mg/kg did not increase

the incidence of liver tumors or produce the

short-term effects that would suggest that they

would be hepatocarcinogenic.

At 13 weeks, I did not show the data, but

at 13 weeks, we saw that there was an increase in

cytotoxicity, there was an increase in labeling

index. We have a stop group, so they were exposed

for 13 weeks, then, they were held for an

additional 4 weeks. Both the labeling index and

the cytotoxicity returned to normal in that group.

There are other chemicals with the same

proposed mechanisms - chloroform, carbon

tetrachloride, theocitamide [ph], a whole variety,

that the mutations or the other events that we saw

in these genotoxicity assays may be secondary to

hepatocyte cytolethality or increased cell

proliferation.

This is a biologically plausible

mechanism. It makes sense that cells are killed,

that new cells are produced, and that these

particular cells may be more susceptible to DNA or

genetic damage.

The furan-induced effects after short term

exposure are inhibited by p450 inhibitors. We said

that furan is metabolized by cytochrome p450-2E1 to

its toxic metabolite, it's a dialdehyde. If you do

studies in which you give the animals the furan and

the p450 inhibitor, you do not get an increase in

labeling index at these doses. You do not get an

increase in cytotoxicity.

There are similar pharmacokinetics in the

mouse and in the human in vitro, and in general,

the rat metabolizes furan slower than does either

the mouse or the human.

Future areas of interest. It would be

interesting to know that if you gave your animals

p450 inhibitors or maybe developed a transgenic

mouse in which that particular gene was knocked

out, would you get mouse liver tumors.

Are liver tumors due to the bolus dose?

So, unlike food where you are taking a little bit

in all the time, we gave them their furan in one

big dose the first thing in the morning.

Are the positive genotoxic results, are

they due to direct damage to the DNA, as some of

the genotoxicity assays indicated, are they due to

the high doses, or are they secondary to cell

proliferation or other phenomenon?

What are the molecular or the gene

expression changes in liver tumors? That is

something that we have been looking at is to try

and find out are there growth factors, are there

other things, surrogate markers that we could find

in the blood that might help us identify those

chemicals that are possibly carcinogenic, in

particular, liver carcinogenesis, and, in

particular, those that do a biocidal toxic

mechanism.

Do these same mechanisms occur for

cholangiocarcinomas? Is there a threshold for--and

I am sorry, these say cholangiosarcomas, they

should be cholangiocarcinomas--is there a threshold

for cholangiosarcomas, similar to what we found

with the mouse liver?

Is the mode of action of the

cholangiocarcinomas similar to that of the mouse?

Do biliary tract epithelial cells have

pharmacokinetic parameters similar to that of

hepatocytes? It is the biliary epithelial cells

that are believed to be the precursors of the

cholangiocarcinomas. What is the relevance of the

mouse liver findings to cholangiocarcinomas and

leukemia in humans?

This particularly has to do with the

pharmacokinetic parameters. What are the

concentrations in the organ systems of interest?

Are there populations of humans that are

susceptible to furan-induced effects and is age a

factor, whether it be the baby food or the elderly?

There is a lot of evidence that indicates that

infants don't have the same intoxification or

detoxification systems as adults, so does that make

them more susceptible or less susceptible?

Finally, I would like to thank my

colleagues, those who actually did the work,

particularly, the--well, anyway, my

colleagues--particularly the toxicology technicians

and the animal care and the laboratory assistants

who certainly did 99 percent of this work, the ILS

Histology Department for the H & E stained liver

sections, Dr. Robert Maronpot at NIEHS, who read

the liver sections, Julie Foley at NIEHS, who

helped with the cell proliferation studies, and Dr.

Tom Goldsworthy.

Questions, please?

Questions of Clarification

DR. MILLER: Dr. McBride.

DR. McBRIDE: I have two questions.

Firstly, is there any data in the mice that is age

related? Secondly, if I am remembering right, you

had the only slide that showed any changes at or

below 2 mg/kg dose was the one slide on

cytotoxicity, I forget how that was measured, and

if I am understanding you right, that was

reversible at least in time.

DR. MOSER: That was in the 13-week study,

so let me see if we can find that data. Do you

know, was that in the 13-week?

DR. McBRIDE: Yes, at the 13-week.

Although it was reversible, it might still be of

import because, of course, as we are looking for

any change, we are looking for the lowest dose,

especially in humans where there may be multiple

factors that affect risk.

In other words, was this the only finding

that you found at 2 or lower mg/kg?

DR. MOSER: I think that we had some cell

proliferation at 3 weeks in this 13-week study, so

there was a significant increase at 2 weeks at 2

mg/kg at 3 weeks, and that is the only significant

finding that we had.

DR. McBRIDE: But on your other slide, it

was a 0.5 mg/kg, the one before that.

DR. MOSER: Okay, and I think what it was

there, it's a statistical thing, we only had 10

animals per group, and we had 2 animals that did

show some evidence of cytotoxicity. These slides

were read blind. It is not a significant increase,

but there is something.

DR. McBRIDE: And the question of age of

mice?

DR. MOSER: Age of mice. All the

short-term studies that we did, the mice were 6 to

8 weeks old when we started, and that is because

the liver continues to divide and is really not

mature until about 10 weeks of age, so we tried to

make sure that all of our studies were done the

same, be they the short term or the long term.

So, that our short-term studies and

long-term studies, they all started exposure at the

same age. It is just that with your 2-year

studies, of course, we went out to the end.

DR. MILLER: Dr. Gray.

DR. GRAY: I think something that we want

to try and learn about here that is really

important for thinking about this food situation is

something you touched on in one of your last

slides, and that is this question of dose rate.

Is there any other data to help us

understand that, because as you mentioned, other

compounds that are thought to act in this way show

a strong dose rate effect. For example, chloroform

gives you very similar mouse liver carcinogenesis

by gavage.

Ninety percent, 100 percent response, you

give the same dose in drinking water over the

course of the day, no tumors at all.

DR. MOSER: Right.

DR. GRAY: And if dose rate is an

important factor here, that is something we need to

know because that is a big difference between our

animal studies here and the way in which people are

likely to be exposed.

So, I mean I don't know if there is

something in the literature you can help us

understand, or if it is something that we need to

think about as a study going forward is

understanding whether there is a strong dose rate

effect for liver tumors and the other tumors that

are out there.

DR. MOSER: Let me say, and that is why I

put it up there, chloroform has a mechanism of

inducing liver tumors that appears to be very

similar to that of furan. If you give chloroform

by gavage, the same way we gave the furan, you will

get liver tumors. You give them the very same dose

in the water, you do not get liver or kidney

tumors.

So, that indicates that maybe small

amounts over the course of time doesn't have the

same effect as just one huge dose, and particularly

maybe first thing in the morning. They are

nocturnal, you know, they move, they do things at

night. So, who knows? But that is a very, very

important thing.

DR. GRAY: And at this point, there really

isn't anything in the literature to help us on the

furan front on this?

DR. MOSER: I think that Greg Kadaras [ph]

has done a little bit of work, and I think it has

been inhalation, and I will have to check on that,

but he has done work that I believe has been by a

mechanism other than gavage.

DR. MILLER: Dr. Krinsky.

DR. KRINSKY: Thank you for the nice

cancer cell biology review. You used the term

"threshold" and "dose dependent." Those are not

identical, and I think that is important in terms

of human consumption, because if, in fact, your

data indicates that there is a threshold level

prior to seeing toxicity, that may have very

important implications as far as human consumption

is concerned.

DR. MOSER: I would agree. The idea of

the threshold is that there is, from my definition,

okay, in this study, is there is a dose below which

you really don't see the cytotoxicity, you don't

see the compensatory cell proliferation, and you

don't see the liver tumors, as compared to dose

response, which means, you know, a low dose you get

a low response, medium dose, medium, high dose,

high response.

DR. KRINSKY: And the mechanism for the

threshold?

DR. MOSER: What we would have to say is

that whether it's a matter of intoxication, you

know, that there is just so many mixed oxidase

function enzymes to produce the toxic metabolite,

or there is a detoxification mechanism, you know,

it is believed that glutathione is a way of

detoxifying the metabolite, and there may well be,

and we know that is the case, only so much

glutathione, so there is only so much to help us

cart that toxic metabolite out. Beyond that level,

you may see toxicity.

But the truth of the matter is, when I

look at the literature, glutathione is the only

detoxification mechanism they have looked at.

There may be others.

DR. MILLER: Dr. Russell.

DR. RUSSELL: Again, thank you for that

presentation. In thinking about populations of

humans that might be susceptible to furan-induced

effects, the one that comes to mind right away to

me is alcohol users, because it is such a potent

stimulator of p450-2E1.

DR. MOSER: Exactly.

DR. RUSSELL: I think that that ought to

be looked at in your model, but in epidemiologic

models if this gets carried on to humans, that this

really may be a population that is much more

susceptible.

DR. MOSER: I think there was a study done

at CIIT, and it was a short-term study in which

they induced the cytochrome p450-2E1 by exposing

the animals to acetone, it was. I don't think it

was the alcohol should have done the same thing.

DR. RUSSELL: Yes.

DR. MOSER: So, you have these higher

levels of the enzyme that is producing the toxic

metabolite, and we also know that certainly alcohol

consumption is a prerequisite to certain kinds of

liver damage and ever certain kinds of liver

cancer, so that is a very good point, and I

wholeheartedly agree. Thank you.

DR. MILLER: Dr. Callery.

DR. CALLERY: Let me probe that 2E1 a

little further. I want to know if you know that

the 2E1 in mice is the same as the human 2E1 is one

question, and then another is, I am probing my own

memory here, do you know Carlson's work at Purdue

on styrene?

DR. MOSER: No, I am sorry, I don't.

DR. CALLERY: I believe he has got a null

2E1 mouse.

DR. MOSER: Oh, does he?

DR. CALLERY: Where the styrene was still

converted to styrene oxide and had the same

viability for potential carcinogenicity.

DR. MOSER: I think that's interesting

because it's like everything else, you know, we

have looked at the 2E1. There may well be other

means of intoxication, we just haven't looked at

them.

DR. CALLERY: Or detoxification.

DR. MOSER: Exactly.

DR. CALLERY: The other is I am trying to

relate the mouse to the human, and especially in

the glutathione concentrations and such, and the

redox activity in the glutathione system. I don't

know how that relates to the human.

DR. MOSER: I don't know either. Does

anybody know if the glutathione levels are

comparable in mice and in humans, or in the liver

anyway? I am sorry, I don't know.

DR. CALLERY: Then, I guess the last one

is you had mentioned that you were at 2 mg/kg and

we have an estimation that the human exposure might

be 1,000-fold less. Does that have any meaning to

you?

DR. MOSER: Well, there is species

extrapolation, as we all know, is extremely

difficult. Not only that, we have got a tissue

extrapolation here, you know, that we are not

necessarily talking about, a high incidence of

liver cancer in this country, not to say that it is

not important, and most of the liver cancer that we

see in this country we believe to be more

associated with hepatitis and alcohol consumption.

So, does that mean that I think that those

levels are safer? Not absolutely at all. It does

appear that the mouse is more sensitive to liver

tumors than some of our other models. Actually, a

better question is well, what about the

cholangiocarcinomas. I mean they saw almost a 90

percent incidence at 2 mg/kg in your NTP bioassay.

Is that relevant?

Well, here, we don't know, at what dose do

you continue to get these cholangiocarcinomas. As

I look at the literature, and I am not an expert on

that by any means, it does appear that the rat is

more sensitive to at least cholangiocarcinomas than

are mice or humans, that in all the reading I have

done in the last week or so trying to prepare for

this, there is only one study in which there was an

increased incidence of cholangiocarcinomas in mice,

and that was with PCBs, polychlorinated biphenyls,

and they were on some sort of a restrictive diet,

and the incidence was not as high as what you are

seeing in your rat.

So, again, we go back to the species is

extrapolation, is that data in rats relevant to

humans at that dose. I wish I knew.

DR. MILLER: Dr. Chesney.

DR. CHESNEY: You just mentioned

hepatitis, and I was thinking that another human

population that might be at risk for furan are

patients with hepatitis B and hepatitis C, and

there is an animal model for hepatitis B, and I am

blocking on the species. I think it might be the

prairie dog, but I am probably wrong about that.

DR. MOSER: Is it the woodchuck?

DR. CHESNEY: It's the woodchuck, that's

right. Thank you.

DR. MOSER: Don't ask me how I knew that.

That just came out of some deep recesses.

DR. MILLER: I am going to call for a

break. Can we be back here in 10 minutes.

[Break.]

Public Comments

DR. MILLER: The FDA received only one

request for public comment, that by the National

Food Processors Association. It was to be

delivered by Dr. Richard Jarman.

Dr. Jarman has said that in the interest

of facilitating the discussion, he submitted a

statement which he intended to read and which you

have all received a copy of, and he is prepared to

allow the statement to stand in lieu of having to

make a presentation.

So, the statement will be incorporated in

the record.

Summary and Charge to the Committee

DR. MILLER: Now we come to the nitty

gritty. Before we begin our discussions, Dr. Terry

Troxell of the FDA will summarize and re-present

the charge and reading of the questions, and then

we will proceed with our discussions.

DR. TROXELL: Thank you. My name is Terry

Troxell, Director, Office of Plant and Dairy Foods.

I don't want to take much of your time. I

just want to recapitulate a little bit to

facilitate your discussion. The main points here

are the actions we take and what are the data

needs, the charge, and the questions.

As we have said, we have developed the

method. The method was posted on the web site. We

are going to be doing a round robin, so we should

sort out any differences in levels being observed.

We did an exploratory survey, more than

160 foods were in our first round, and with 40 more

since we published a notice in the Federal

foods, and we will be testing a broader range of

foods.

The preliminary exposure assessment was

done. We utilized the first 160 samples,

obviously, because things are moving so fast, we

were not able to incorporate all the data that we

pulled recently.

We also obviously did our call for data

and then we have established international

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interactions. We provided Canada with our method,

and they very quickly developed additional methods,

similar, so that we could generate a lot of data

together, and we also coordinated, so that we could

minimize duplication of effort, so that we can

maximize the results at this point.

The other thing you should be aware of is

that the EU has a heat tox project, which is to

look at investigating thermally processed induced

toxins in foods, and they are going to incorporate

furan in that process.

So, again, as with acrylamide, we are

trying to maximize our collaborations to try to

zero in on the problem as soon as possible.

Some future actions, of course, we still

have another 30 days to go on our data call, and

then we will evaluate that data, the whole group of

data. We will take the tox studies to our Cancer

Assessment Committee or CFSAN's internal expert

group to have a look at the overall picture and to

help us decide where to go from there.

We also want to develop an action plan to

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provide guidance, not only for FDA, but also in our

broader collaboration efforts, so that we can

adequately assess the risk, and, of course, to

serve as a basis for risk management.

Data needs. Or course, we need a broader

range of foods in which furan occurs. We need to

know the levels of furan in these foods, and then,

of course, the formation and occurrence in

home-prepared foods.

We have been working on a hypothesis that

pretty much if you cook the food in a hermetically

sealed container, like a can or jar, whatever is

formed in there is trapped and can't escape,

whereas, other foods, such as potato chips, which

are produced in an open line, or cereal, or so on,

that a significant amount of degassing would occur

or volatilization would occur either in the

processing environment or subsequent through

diffusion.

So, then, it gets to the question of what

happens in the home environment, what happens in

the retail environment, where you might generate

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some furan, and it does not have time for

dissipation, so, yes, we do need to flesh out what

is happening in the home environment, which also

would be relevant to a retail environment.

The other consideration we need to bring

into this is other environmental sources of

exposure to furan, such as from smoking, there is a

range of possible areas.

We have here possible mechanisms of furan

formation. In addition to possible mechanisms,

what we would be most interested is the principal

mechanism of formation during standard process in

home cooking.

We also have variables that enhance or

mitigate furan formation, stability, or dissipation

of furan in foods. Again, that goes to the

dissipation over time, for example, and the

stabilization with fats in the food, effects of

post-production practice on furan levels.

Then, we have quite a few areas of

toxicological needs, mechanism of furan and

toxicity, mutagenicity, and carcinogenicity, the

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reproductive and developmental toxicology of furan.

We have basically zero on that to my knowledge.

The metabolism of furan in vivo including

characterization of reactive furan metabolites.

The diversity of furan pharmacokinetics in

humans or the alteration of furan metabolism as a

result of dietary, medical, or environmental

interactions.

Data on whether sub-cytotoxic furan doses

produce any adverse effects, such as a change in

enzyme activities or ATP levels.

The effects of furan doses lower than

those used in the NTP study: to establish a

dose-response curve for various tox endpoints; to

determine whether furan toxicity including

carcinogenicity is a threshold dependent event; and

to determine whether carcinogenic activity is

secondary to hepatotoxic effects.

Still more. The mutagenicity of furan in

the TA100 strain in the Ames test. It was weakly

positive in one study, but negative in all Ames

strains in the NTP study. The behavior of furan in

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other in vivo assays for mutagenicity or toxicity.

Then, that brings us to the charge, which

is in Tab 2 of your notebook. That is the Food

Advisory Committee and Contaminants and Natural

Toxicants Subcommittee are being asked to provide

input on the data that would be helpful for further

evaluation of potential risks posed by the presence

of furan in food.

Then, the question which I will leave up

here to help discussion. Taking into consideration

the data needs already identified in the Federal

presentations at this meeting, are there any

additional data that are needed to fully assess the

risk of furan in food?

The data needs we identified are fairly

broad. Are there still gaps? What are the

important missing data for assessing the human

health impact from furan in food? Since there are

studies available in some of the areas, such as

mutagenicity, which areas need particular fleshing

out and in what ways?

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I guess this is what to me is encapsulated

in the broad question. Finally, I want to thank

you very much for your critical input here. We are

at a very early stage in this process in trying to

get our arms around this issue, and it is very

important to have your thoughts to help us do the

right set of work and develop the action plan, to

guide our efforts for the future.

Thank you very much and I can try to

answer questions that may be lingering and, if not,

we can have our experts answer those I cannot

before you start your discussion.

Questions of Clarification

DR. DWYER: Dr. Troxell, a couple of

months ago, i think it was, or maybe longer, we

discussed acrylamide in food, and I wonder if there

is a sort of a large plan to look at all the

heat-formed compounds that seem to be of concern,

and is this part of it, or how is that being

handled, the big picture?

DR. TROXELL: We have no comprehensive

program to look at them. The EU has this heat tox

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program that they put a fairly large sum of money

in to work on, on thermally generated toxins. We

are collaborating with them, I mean interacting

and, as I said, we have contributed a new one to

their effort.

DR. ACHOLONU: We are told that you have

checked different kinds of foodstuffs so far, and

you have plans to do more. Have you been checking

these randomly, or do you have a special pattern

that you are using to select the foodstuffs to

check for furan?

DR. TROXELL: Well, again, the theory we

used for several fold. Those foods we expected to

contain furan, such as the canned and jarred foods,

and also even if we expect at the levels to be on

the low end, we also wanted to check the foods that

were major contributors to the diet, such as the

apple juice for the children.

So, yes, we have a strategy, and as with

acrylamide, we will focus in on those foods which

seem to be the major contributors and look at those

intensely, but also expand more broadly to make

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sure we haven't missed anything, and over time, we

have picked up a few additional items that have

contribute.

So, we have to start at the first base and

we will keep digging in until we kind of flesh it

out more completely, and with our collaboration

with Canada and hopefully the EU, hopefully, we

will get to fairly comprehensive understanding of

the foods that contribute significantly to the

exposure.

DR. MILLER: Dr. Waslien.

DR. WASLIEN: The total diet study

analyzes now for toxicant suppression in food as

well as vitamins, and I would think that it might

be worth investigating to see about collaboration

with that process, too, just to get a better mix of

foods, say, go out and buy it, you know, a

systemized fashion, and you can get an overall view

of exposure in the U.S. diet, and it may identify

at least for one shot, groups of foods, maybe that

way more easily.

DR. MILLER: Dr. Lee.

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DR. LEE: I was just wondering, I guess

furan has been looked at by flavor chemists because

it is part of the flavor, taste of food. Does it

actually have a role in food acceptance or it is

just an incidental compound that has no measurable

positive impact on food?

DR. TROXELL: I can't answer that

precisely. I know the class of foods, the class of

chemicals is known as the furans of various

derivatives. Some of those would have a role in

flavor chemistry. I don't know that furan per se

has a role in flavor chemistry. Certainly, once

you start getting into that class and you get side

reactions and decomposition, and so on, you are

going to end up with tiny amounts of furan in foods

as we have found, and with the new analytical

technology, we are now able to tease out very

precisely what couldn't easily be seen back in '74,

for example.

DR. MILLER: Dr. Lund.

DR. LUND: Relative to occurrence and

exposure, you mentioned specifically home-prepared

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foods. Are you also going to be looking at food

service preparations in restaurants?

DR. TROXELL: This is a good comment, and

I think many of the approaches used in restaurants

are the same approaches used in the home. I mean we

have to look at microwaving, and so on, to see what

generates food, what generates furan, you know, at

levels that don't dissipate by the time the

consumer ingests the food.

It is the same problem, of course, with

the total diet study. We have worked on volatile

organics and I don't know what protocols we used

there, but we have to be careful that, you know,

those foods are analyzed ready to eat, but by the

time, you know, they are prepared by a church

group, and if they are not specially processed

after they are cooked, we could lose whatever furan

was formed, and it will not be as consumed, so we

need to be very careful that if we do such a study,

we end up with something that mimics as consumed.

DR. MILLER: Dr. Nelson.

DR. NELSON: I just wanted to follow up on

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Dr. Lee's question about the flavors. I don't

believe furan is itself a flavor compound, but

furanial is and furferal [ph] is, and I believe

FEMA, the Flavor and Extract Manufacturers

Association, has done a toxicological review, that

they are pretty well clear.

DR. MILLER: Jean.

MS. HALLORAN: Earlier, you had a few

cases where you heated the canned foods and had

some interesting results. Are you going to do any

more with the canned foods to attempt to mimic

preparation, normal preparation situations?

DR. TROXELL: Yes, I think whether it be

the canned foods, whether it be a soup that is put

in the microwave and heated to see if that

increases the levels or not, of other foods that

are cooked that might generate from the get-go

whether we might have furan in an oven-baked food,

I think we probably have to check some of those

things out just to cover the territory, so we

understand the dimensions of the exposure.

DR. MILLER: Dr. McBride.

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DR. McBRIDE: A couple of questions. Do

we know anything in the animals about serum levels?

I am not even sure that serum levels are valid

because the boiling point is below body

temperature, and probably first pass to the lungs,

it is pretty well out of there, but do we know

anything about serum levels in animals?

DR. MOSER: No.

DR. McBRIDE: I don't know whether that is

worth pursuing or not. Also, do we know anything

about furan exposure industrially in humans?

DR. TROXELL: I don't know anything about

it. Certainly, there would be a component of

interest, but it would probably be a small portion

of the population, and if you are thinking of using

such a group, for example, to look at epidemiology

to see if there is an increase of tumors that way,

such as was done with acrylamide, that certainly is

a question that could be asked.

I do believe on your other question that

there is some comparative metabolism studies in

different animals on furan, although I don't know

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that there is serum levels, but there certainly is

as compared to metabolism, I believe.

DR. McBRIDE: But it would probably be the

two issues, you know, whatever wasn't metabolized

in the liver may or may not stick around in serum,

probably wouldn't by the boiling point, but I am

not sure.

DR. TROXELL: I think it is cleared fairly

fast, I think the half-life is fairly short.

DR. McBRIDE: Another, at-risk population

might be smokers.

DR. TROXELL: Absolutely.

DR. McBRIDE: Houses with lots of smokers,

that sort of thing.

DR. MILLER: Dr. Chesney.

DR. CHESNEY: I have one specific question

and then I have a whole list of suggestions. Is it

appropriate to do that now or did you want to wait?

DR. MILLER: Why don't we wait until we

finish with Dr. Troxell.

DR. CHESNEY: The more specific

suggestion, people are mentioning other things to

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test. I wondered if it would be worth testing

intravenous and parenteral preparations that are

given to humans because a lot of them have lipid in

them, are given continuously for long periods of

time, and they are often warmed or heated before

they are given.

DR. TROXELL: You mean intravenous or tube

feeding?

DR. CHESNEY: Both. The tube fed ones do

come in cans, and the intravenous ones obviously--

DR. TROXELL: There is also a time factor.

To put it in context, there is a time factor here

in that we are talking about generally chronic

effects, so if you are talking about a short-term

exposure, even though we may be particularly

concerned because it is higher or a worse case

exposure, the effects we are talking about

generally are chronic exposures, so we should put

them in our equation what we look at.

DR. CHESNEY: I understand, but we have

children, for example, who are on parenteral

preparations for years because they have had their

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GI tracts removed, or many people are fed enterally

for other reasons continuously for years and years.

DR. TROXELL: It would be good to check.

DR. MILLER: Dr. Downer.

DR. DOWNER: I am just going back to Dr.

McBride's question about environmental exposure.

We did mention cigarettes, but also I read in one

of the studies that exposure or people who are

bakers, who are expose to baked bread, that was

also an environmental exposure risk, so perhaps we

may also want to look at individuals who are in the

baking industry to see if perhaps there is some

consideration there.

DR. MILLER: Dr. Chin.

DR. CHIN: I just want to actually go back

to something that Dr. Beru mentioned. Just for

point of clarification, I thought that he said that

when FDA did the initial assessment of the risk,

that you took the work that was done by the

National Academy of Sciences and NASA, and you came

up with a NOEL of 80 mcg/kg per day, I believe.

DR. TROXELL: National Academy came up

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with number.

Committee Discussion and Recommendations

DR. MILLER: If there are no more direct

questions, he will be here in case the issues come

up again.

So, now the time comes for us to start

making some recommendations for studies that ought

to be done, that have not been thought of by the

agency.

The question is what can we add to their

action plan that would be useful. I am sure you

all have your favorite lists. A number of them

have already come up in our discussion. The impact

of development on metabolism of furans, I think

was one of the earlier ones, and I think that is a

very important issue, particularly given the fact

that there is a substantial part of the exposure is

in infants, and so we need to know better whether

or not there is a difference in the sensitivity of

infants or elderly, for that matter.

The question of dose rate, all the

experiments that have been done so far have been

116

done with daily bolus and there is some suggestion

that there may be a difference between bolus

exposure and continuous exposure, and that becomes

very important from a methodological point of view,

as well as from the point of view of trying to

interpret the potential hazards associated with

furan exposure.

Another interesting one that came up in

the first part of the discussion is the question of

glutathione, is glutathione the biological

detoxification step, the principal biological

detoxification step for furans, and if it is, can

you associate things such as the cytotoxicity of

furans with the regulation of the glutathione.

That it seems to me needs to be done.

The question of food service has come up

quite a bit. I am not so sure it's true, Terry,

that the processes used in food service,

preparation of food are identical to those used in

the home. They are often cooked at higher

temperatures and maybe for shorter times, so I

think it would be worthwhile to take that into

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account in determining your sampling program.

The other thing that occurred to me, and I

may have missed it, but I didn't see anything on

mother's milk, how much of mother's milk, how much

of furan or of the metabolites, potentially toxic

metabolites of furan show up in mother's milk.

I think, Dr. Chesney, you said you had a

long list.

DR. CHESNEY: Is it my turn?

DR. MILLER: It's your turn.

DR. CHESNEY: Thank you very much.

Let me just start with a general overview.

As you know, we have a very yuppified generation of

young parents out there, and I think as soon as

they hear more about this, they are going to be

quite active and involved, and I know you have

anticipated that, but the first thing I wanted to

mention is very simple, and that is that it might

be interesting to look at levels of furan in

home-prepared baby food.

This was very much in 20 or 25 years ago,

and it was a lot of work, and so I didn't last very

118

long with that, but that is certainly something

that you would be able to give a very quick answer

to people if they had questions about if I made my

baby food at home, and didn't heat it, would my

infant be better off.

So, my other issues, obviously, as

pediatricians, we think very much developmentally.

We think about the mother-fetus diad, and then the

newborn who is very immature in many respects, and

then the infant and ultimately the child.

So, in terms of we wonder about tissue

penetration, tissue concentration, and impaired

metabolism and excretion depending on the age. So,

starting with the maternal fetal model, I think

maybe using animal models of pregnant mice or rats,

and then newly delivered mice or rats to look at

issues of transmission, is there enhanced

transmission across the placenta, is the placenta

particularly concentrated in terms of furan or none

at all.

And then I also had breast milk on my

list, is a very important issue, and somehow it may

119

be even clinically in humans ultimately tying

levels in breast milk to levels that the mother

ingested in the recent past.

And then turning to the newborn, we have

seen the levels in formula and infant food, but the

newborn GI tract is a relatively porous organ, and

i don't remember enough of my GI pathophysiology to

remember how long that goes on, but is there

enhanced furan uptake in the first few weeks or

month of life, and does it concentrate in other

tissues and/or pass into other tissues.

We have talked about the liver and the

background materials we were given, talked about

the kidney, but obviously, again in terms of

development, as pediatricians, we are always very

worried about the brain. Could studies be done in

fetal and infant animals to show whether the furan

is penetrating the brain because that is a question

that will come up very quickly when more and more

people learn about this.

Questions about infant PK studies of

furan, again maybe before and after ingestion. The

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issue of home preparations and finally sick

infants. We have a lot of children who come in for

fairly acute self-limited illnesses that do develop

liver damage, transient liver damage, and then we

have large populations of premature infants and ill

infants who spend prolonged periods of time in the

hospital, who often are fed with these intravenous

or nasogastric preparations, and they often also

have underlying liver disease in part because they

get the intravenous parenteral preparations.

So, if there were any question about

significant furan levels and what we are giving

them on top of the fact that they already have

cytotoxic liver damage in many cases depending on

the underlying disease, I think that would be

important to know.

That is my list for the moment.

DR. MILLER: Good. Thank you very much.

DR. KRINSKY: I just want to point out

that once you move from the food into the animal or

the human, that furan is not the only thing that

should be analyzed because furan is not the active

121

component, furan is metabolized, and I think we

have to have information about what the metabolites

are, what the active metabolites is, and whether,

in fact, this can be assayed in tissues, in fluids,

or anything of that nature, but not just the furan.

DR. MILLER: Dr. McBride.

DR. McBRIDE: I think it is a good

suggestion to look at it in breast milk, and again,

one might want to look at it in the at-risk group,

smokers, for instance, versus non-smokers or

something like that.

The second suggestion is in looking for

mutagenicity, one might want to do

second-generation studies in the rats especially in

the females.

DR. MILLER: That is a good idea.

Dr. Callery.

DR. CALLERY: About the metabolism and

follow-up on what we just heard about the metabolic

activation, I am wondering if there isn't the use

of the Ames test, not just for furan, but also in

the presence of human liver microsomes, such that

122

it would have a bioactivation potential to screen

for mutagenicity.

The comment about glutathione as a

detoxification pathway, the compound that is in the

literature that is the potential mutagen is a

sis-buten-dialdehyde [ph], which I believe has been

shown to be mutagenic in some system.

But the way that that compound may also be

detoxified in addition to glutathione or other

sulfhydryl compounds is by oxidation of the

aldehyde and further conjugation of those products.

So, beyond the cytochrome p450s are the soluble

enzymes, probably the aldehyde dehydrogenase or

aldehyde oxidase that would certainly want to be

looked at.

The comment about the infant and aged, in

their metabolism, if this is a metabolically

activated compound, it might be advantageous to the

newborn not to have 2E1 and another p450 isoforms

might be to their benefit.

So, that might beg the question of whether

you want to do any even--I don't know if there is

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genotyping, pharmacogenomic issues about whether

2E1 is available and in different population sets

or if you wanted to actually consider relating 2E1

concentration to potential for mutagenicity.

I had another comment that was about the

broader collaborations that we have been hearing

about and especially since one of the issue here is

the mechanistic aspect of how this substance might

be bioactivated, is the possibility of working with

NIH to have the National Institutes of Health

consider an RFA on the mechanisms of this, and then

when you look to the comments of the workplace

exposure to furan might also involve a

collaborative association with the EPA.

DR. MILLER: Dr. Gray.

DR. GRAY: Thank you. I have just got two

areas that I would like to comment on. I think

that there is really no way that we can continue in

a situation where we haven't done reproductive and

developmental tox on this material, and it just

seems to me that that is one of the things that

should be in an action plan pretty quickly, at

124

least getting some feel for this.

Some other compounds that act like it, it

is probably not something where there is a serious

concern there, but it is just the kind of

information I think that needs to be developed in a

fairly short time.

The other thing I wanted to do is to

encourage the work on the mechanisms of formation.

I think that is a really important thing, and I

think it is important for a reason that was

actually raised by Jim Coglin in his letter that he

submitted.

This already looks like it is in. I think

the estimate that we just saw it's in about 20

percent of the food supply now, and that's not

consumption weighted, but 20 percent of the food

supply, it may end up in 30 percent or 40 percent.

We are not going to be able to avoid it.

Then, we are going to have to start

thinking about ways in which we will try to manage

it, and I think it will be important about

understanding the mechanism is by in managing that,

125

we want to make sure that we are not making risks

worse, that some of the things we have talked

about, like pasteurization, have their own real

benefits that we have to understand.

So, if we can understand the mechanisms,

perhaps we can design ways to control it if that is

necessary, but we can at least keep in mind the

tradeoffs that we might face. So, this is just I

think a plea to continue working the great work

that has been done in Canada, work that is being

done in FDA, to try and move along the mechanisms,

so we don't find ourselves making things worse by

trying to address this problem.

DR. MILLER: Thank you.

I think ideas like that were incorporated

in the plan. I say that only because it is

important to reiterate it because I think it is a

basic thing. The issue for these adventitious

contaminants that are natural products, the only

thing you can do is mitigate them. You can't bann

the food.

DR. GRAY: I don't want to give up my

126

coffee.

DR. MILLER: That's always a personal

thing.

Dr. Downer.

DR. DOWNER: I agree with what my

colleagues have said, I just wanted to add a little

bit by saying we really need to do some more

comprehensive data on the furan that is found in

foods and beverages, and perhaps using the U.S.

data tapes or some of the NHANES data or some other

database, so that we can get a better perspective

of the different kinds of foods and groups of foods

in particular and the furan levels in them.

Also, I think it would be good if we found

that we should establish an acceptable level. If

furan level is low, then, we might not need to

implement a risk management protocol, but if it is

higher than the level that was established, then,

we will want to do some interventions then.

I go back to what you said, Dr. Miller. I

concur because we really don't prepare foods at

home as we do in a restaurant. We haven't look at

127

condiments, for example. We don't know the impact

of that. It may be small, but it may be

significant.

So, I think it would be prudent for us if

we look to see if there are any risks in food

preparation and packaging. We may want to look at

home prepared, restaurant prepared, as well as

pre-packaged foods to see what levels may be there,

as well.

DR. MILLER: Dr. Lund.

DR. LUND: Just to follow up with regard

to the types of processes that ought to be looked

at. It would be good to look at a couple of the

newer processes. You might not expect to see much

furan formation in high pressure processing, for

example, but it is certainly an alternative for

thermal processing in some cases, and at some point

needs to be looked at among other processes, as

well.

DR. MILLER: Dr. Dwyer.

DR. DWYER: I think I share other people's

concern that a wide variety of possible suspects

128

among foods be look at, not just the ones that have

been looked at. I am still puzzle by this business

of heat formed compounds occurring together. Last

year, we heard that potato chips were very high in

acrylamide.

So, is it because all the acrylamide is

taking up the main line of reaction, who knows.

The second thing I am concerned about is

the whole issue of risk and the sensitivities that

have been mentioned. I believe Dr. Russell

mentioned alcohol. Dr. Krinsky mentioned I think

hepatitis B and C, smokers have been mentioned.

Coffee has been mentioned, but only in a positive

context, it might have some effects that would be

worth looking at, and then I wonder about common

OTC, particularly OTC, but also perhaps prescribed

drugs that might affect those same systems as being

important to at least take a look at.

The final area has to do with mechanisms

and metabolism, the issue of dose rate of

compounds, is there a threshold versus the dose

response business, the issue of getting common

129

methodologies so we don't overduplicate all seem to

be important.

DR. MILLER: Thank you.

Dr. Lee.

DR. LEE: I suppose if the FDA could wave

its magic regulatory wand and eliminate all of this

compound in food effective tomorrow, but the

question needs to be asked, is the human condition

going to be substantially improved, and I just

don't know if you have got there yet.

Particularly, I would like to see what the

relative exposure is to humans from other sources

of furan. I don't have a good feel for that, is

food really the problem, or is it just that we are

sensitive to it because it is showing up in foods

and things that we think ought to be absolutely

pure.

I think that is really a very subjective

judgment whether or not the human condition is

improved by elimination of the compound, but we

need the data on where the problems lie outside of

the food system.

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DR. MILLER: That's a good point, but the

problem is that you can't answer that question

until you know all this other stuff, and I think in

the end, that is what the goal ought to be. Or

course, there are others, it is going to depend

upon the agency's decisionmaking, but that should

be the primary goal.

Dr. Chin.

DR. CHIN: I guess one area that I guess

gets back to the basics in terms of measuring

furan, and I know that a lot of work has been done

already in terms of validating the methodology, but

as we got further into this and especially as

people make decisions or make assessments, I think

we need to probably do more work on the

methodology, you know, more collaborative study,

maybe develop some type of an official or

standardized methodology.

We also probably need to make absolutely

sure that we are neither producing the furan during

the analysis, nor are we missing the furan in

analysis. So, I think those issues still need to

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be looked at as we go forward.

DR. MILLER: Dr. Acholonu.

DR. ACHOLONU: We are told that FDA has

found measurable furan in jarred baby foods, in

canned infant foods, in canned adult foods,

emphasizing can and jar. It may be necessary to

find out if the jars and the cans have anything to

do with the concentration of furan in the food.

That is a suggestion I would like to make.

DR. MILLER: The situation that has to be

looked at, and the situation like this is a

risk-risk situation, what are the risks of doing

something versus the risks of not doing something.

In other words, if you give up reprocessing of

foods, what is the hazard associated with that,

too? I think that is the question that you were

asking.

DR. ACHOLONU: The can itself, the can,

the jar. Does the can have anything to do with the

content?

DR. MILLER: Packaging.

DR. ACHOLONU: Yes.

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DR. MILLER: Your question is the

packaging.

DR. ACHOLONU: And this you can do by

comparing, as they test different kinds of foods,

get the ones in jars and cans, and the ones that

are not in jars and cans, and compare them, and

find out if there is any difference, and then use

that to make some extrapolation.

DR. MILLER: That issue has arisen several

times concerning the packaging. It is not the only

thing that you have to worry about, there are other

kinds of packaging that might be a problem.

DR. MILLER: Dr. Chesney.

DR. CHESNEY: I haven't heard anything

about serum levels of furan or its metabolites. Do

we know if it is normally detectable in normal

humans, or has anyone looked for furan levels in

serum, or the metabolites?

DR. MOSER: I think that there has been a

PD/PK model, pharmacodynamic, pharmacokinetically

based model, in which they predicted serum levels,

but I am not sure that they actually quantified

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them.

DR. CHESNEY: So, they have never actually

drawn blood and tested it in humans.

DR. MOSER: Not that I know of.

DR. CHESNEY: I think Dr. Lee's point is

very important, that this may be nothing, this may

be a nothing issue and we have to be very careful

not to overreact, but certainly, as I mentioned,

when the yuppie population hears that it is in

infant formula, they are going to become very

alarmed, and I think it might be nice to have some

sort of very--if the methodology is out there for

measuring normal furan levels and serum, and just

doing a very simple PK/PD study based on ingestion

of high furan foods and low furan foods. That

seems like it would be fairy straightforward.

DR. MILLER: I would only modify that by

saying that whatever the principal toxic

metabolites are may be more important than looking

for furans.

DR. CHESNEY: I agree. I keep saying

furans, but furan or its metabolites or just its

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metabolites.

DR. MILLER: Good. Dr. Krinsky.

DR. KRINSKY: I just want to emphasize the

potential nothing aspect of what we are dealing

with, and since we don't know, we don't know what

the levels are that might be toxic, we don't know

whether we can achieve that level with the diet.

There is so much that we don't know about this that

that is why we have a series of questions where

there are things that we want to have done.

What concerns me is that the FDA will

treat this in an appropriate fashion. I must say

that I am very concerned about the people sitting

behind us. I don't know how many of them are from

the press, but I am really concerned about how the

press is going to interpret what we are raising

here in terms of furan in foods.

We don't know if what we are looking at is

potentially harmful. We don't know if it is

harmful. We don't know if it is potentially

harmful, and yet I think what we have been talking

about can be misinterpreted so easily that I would

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like to censor any press release that comes out

from behind us.

DR. DWYER: Go the pentagon, this is the

wrong agency.

DR. MILLER: That temptation is never

fulfilled.

You are right, of course, I mean this

committee was not put together to consider that

issue, but nevertheless, I don't see how you can

come to any conclusions unless you do the

experiments to get the data to see whether it's a

problem of not, and it may turn out to be nothing,

but you have got to do the experiments to find that

out. You just can't ignore it.

Dr. McBride.

DR. McBRIDE: Along with that, we don't

want to spend a lot of the agency's money looking

at something that may turn out to be a non-entity.

Again, back to the serum levels. It seems

to me the first place to look is those rats that

got those high doses, because if it isn't there,

chances of our finding it in the human are small,

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and, of course, looking at the brain, a high lipid

organ, as well.

I was in my wildest dreams trying to

figure out what groups of kids would we go, and how

would we even approach the mom, but there are a

group of kids who are actually orange from eating

so many sweet potatoes out of the jar, so if we

feel a need to go to humans, that might be one.

DR. MILLER: Dr. Chesney.

DR. CHESNEY: In response to Dr. Krinsky's

comment, I think, as we said, this may turn out to

be nothing, but I really would like to commend the

FDA for making this public so quickly in your

deliberations.

I mean you keep coming back to the May 7th

on the web, and most of us go to the Federal

there immediately, and I don't know how you could

do otherwise, and I think that that is the most

important message. We don't know what this means,

but we are letting you know that we are looking at

it, and so I just wanted to make that comment.

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DR. MILLER: Thank you.

Any other comments? Any other

suggestions?

DR. CHIN: I guess just to reiterate, it

seems to me that the most important piece of

information that we need is to come to some closure

in terms of whether or not a threshold exists and

what that threshold level might be, and so either

the continuation of the work that was reported by

Dr. Moser or something along those lines, I think

it is very important because that is really going

to guide us in terms of how much more resources to

put into this issue.

DR. MILLER: To answer the question, I

think some kind of risk assessment is going to have

to be made. It is not going to be a very good risk

assessment because they don't have all of the data

that they are going to need, but they need to have

some ballpark figure.

If I had to personally mark a suggestion

concerning this, I would make that my highest

priority, develop that data that allows me to make

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a risk assessment.

Also, I think from a regulatory point of

view, I think if you do this risk assessment, you

also should be doing risk assessment about what

would happen if you weren't able to process food

according to the technologies that we have

available.

Dr. Waslien.

DR. WASLIEN: That would eliminate me for

the Atkins Diet, wouldn't it?

[Laughter.]

DR. WASLIEN: As part of that risk, I

think you said that once mice or the rats were off

of the diet, that you saw the disappearance of any

carcinogenic effect, so it is not cumulative, so

it's purely a sort of short duration or ongoing

exposure that has to be present, or was that

documented enough?

DR. MOSER: There is also data that

demonstrates that one high dose was able to produce

tumors two years down the road. There was also a

stop group that got higher doses than we gave them.

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They got that for 13 weeks. Then, that exposure

was stopped, and they found increased lesions as

compared to the group that was continuously

exposed.

DR. WASLIEN: Then, concentration effects

are part of the metabolism you have to look at,

too. Thank you.

DR. MILLER: Any other comments? If not,

that's very good. I am not going to even try to

summarize all of the very good suggestions that

have been made. I wanted to keep them for the end

of the meeting, so that in the preparation of the

report of the committee, summary of the meeting,

from the transcript, all of these would be in one

place and make it easier to identify these

recommendations to the agency. For that, I thank

you.

The next step is to develop a verbatim

transcript of the deliberations of the committee,

and that will be made available on the internet,

and then a summary document of the committee's

deliberations will also be prepared, and we will

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share that with you directly.

I have nothing more to add except to thank

you all very much. I appreciate you remaining

focused and disciplined generally.

Terry, do you have something to say?

DR. TROXELL: I just would like to say for

the Center for Food, Safety, and Applied Nutrition,

and FDA, thank you for your two days of close

attention and careful and well thought out input,

and we know it is a tremendous effort out of your

busy schedules to do this for us, but it is

invaluable and thank you for myself, Dr. Laura

Tarentino, and the rest of FDA.

DR. MILLER: Thank you, Terry.

Hope you all make your planes and I want

to thank you personally very much for being a very

good committee.

We are adjourned.

[Whereupon, at 5:00 p.m., the hearing

adjourned.]

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