Many people have been concerned with microwave and irradiation effects on packaging plastics. Most of this concern originates from a hoax email that relates microwaving plastic and cancer. You can read information about this hoax on my Web site:
All packaging materials in direct contact with food must be safe for their intended use under the Federal Food, Drug and Cosmetic Act (FFDCA). The manufacturer of a new material must petition the U.S. FDA and provide data proving the material is safe to use if it is not already regulated for the proposed use. Packaging for irradiation must be separately approved. The packaging comes into direct contact with food so it cannot be composed of substances that might migrate into the food as a consequence of the irradiation process.
In addition, these packaging materials cannot demonstrate detectable radioactivity as a result of irradiation. FDA regulations specify a maximum absorbed dose level of irradiation that the packaging material can be safely subjected to. The package label must exhibit the irradiation logo and a statement such as, "Treated with (or by) irradiation."
Brian A. Nummer, PhD.
Extension Food Safety Specialist
Utah State University
8700 Old Main Hill
Logan, Utah 84322-8700