ARS | Publication request: Effect of Koshering and Hydrodynamic Pressure on Beef Color, Odor and Microbial Loads

Submitted to: Journal Of Muscle Foods
Publication Acceptance Date: November 11, 2003
Publication Date: April 5, 2004
Citation: Holzer, Z., Berry, B.W., Williams Campbell, A.M., Spanier, A., Solomon, M.B. 2004. Effect Of Koshering And Hydrodynamic Pressure On Beef Color, Odor And Microbial Loads. Journal Of Muscle Foods. V. 15. P. 69-82.

Interpretive Summary: A significant problem resulting from salted/koshered meat is the loss of red lean color. Vacuum packaged koshered meat has been criticized for undergoing a rapid color change (red to brown) and developing an objectionable odor during refrigerated storage. The hydrodynamic pressure process (HDP) has been shown to disrupt the physical structure of cellular meat proteins and reduce endigenous microflora. Perhaps the HDP process may interfere with the negative quality changes observed when salting/koshering meat. An experiment was conducted consisting of four treatments. The treatments were: (1) control-nontreated, (2) koshered/salted meat; (3) HDP-treated meat, and (4) the combination of salting followed by HDP treatment. Results indicated that HDP was more effective at reducing the surface microflora of the meat after 14 days of refrigerated storage than either salting or the combination of salting with HDP. Color stability was assessed by both a subjective panel and using a color meter. Both methods found a dramatic discoloration in the salted meat. This discoloration was significantly reduced when HDP was combined with the salting process. Thus it appears that HDP may diminish the undesirable discoloration resulting from salting/kosher processing of meat.

Technical Abstract: Vacuum packaged koshered meat typically undergoes a rapid color change (turning brown) with the formation of objectionable odor during refrigeration. The objective of the present study was to assess the effects of koshering process and hydrodynamic pressure (HDP), either alone or in combination, on pH, microbial growth, color and odor properties of beef. An experiment was carried out on strip loins removed from Angus crossbred steer carcasses. Each loin was divided into four treatments. The treatments were: (1) control (C); (2) koshering process (salted = S); (3) hydrodynamic pressure treated (H); (4) the combination of koshering followed by HDP treatment (SH). The samples were analyzed on day 0 and after 14 days of refrigerated vacuum storage, for bacterial growth, pH, color stability and off-odor. The H treatment was more effective in inhibiting the normal microflora than either S or the combination of S with H. After 14 days of storage, S samples had greater than 80 percent surface discoloration (brown color) compared to less than 40 percent discoloration on the surface for the C, H and SH samples. The H pressure treatment reduced the surface discoloration of koshered (salted) meat samples to a level similar to that of the control. It appears that hydrodynamic pressure treatment may diminish the undesirable pro-oxidant effects (discoloration) of koshering (salting) beef.