As part of its approval, FDA requires that irradiated foods include labeling with either the statement "treated with radiation" or "treated by irradiation," along with the international symbol for irradiation, the Radura (see photo above.) Irradiation labeling requirements apply only to foods sold in stores. For example, irradiated spices or fresh strawberries should be labeled. Irradiation labeling does not apply to restaurant foods.
Source: Excerpted from FDA/CFSAN Food Safety A to Z Reference Guide, September 2001