ONLINE EXCLUSIVE: Toxicological Safety of Irradiated Foods

Editor’s Note: This article is excerpted from a chapter in “Food Irradiation Research and Technology,” which was edited by Christopher H. Sommers, PhD, and Xuetong Fan, PhD. The book was published in 2006 by Wiley-Blackwell, which also publishes Food Quality magazine. To download the full article and references, click here.

Generation of cancers in animals requires the mutation or deletion of oncogenes or tumor suppressor genes, resulting in a loss of heterozygosity at those allele locations. Mutation (point mutations or frame-shift mutations) and deletion of genes can be induced by exposure of cells to genotoxic chemicals or can occur naturally as part of the cellular DNA repair and replication process.

Many consumers are simply unaware that foods contain carcinogens, either natural or artificial, and cause cancer. A very small subset of naturally occurring carcinogens in foods include compounds such as benzene and formaldehyde. A number of studies have confirmed the mutagenicity of cooked meats and their fats, and the formation of nitrosamines as part of the meat curing and cooking process.

Tumor promoters present in cooked meat and poultry include oxidization products of fats and oils, heme, and cholesterol. Alcohol is known to induce the formation of tumors in the gastrointestinal tract of rodents. It was recently found that high-temperature frying and baking of starch-containing foods results in the formation of acrylamide, a suspected human carcinogen. Furan, a carcinogen in animals, is formed in foods as a result of thermal processing.

Compounds used in the pickling, salting, and smoking processes are associated with gastrointestinal cancers in humans. Discussions pertaining to food irradiation, therefore, have to be placed in context with the risks associated with consumption of irradiated foods versus foods processed using technologies and additives that are known to cause cancer in animals and humans.

Food Irradiation

Food irradiation is perhaps the single most studied food processing technology for toxicological safety in the history of food preservation. Studies pertaining to the safety and nutritional adequacy of irradiated foods date back to the 1950s and were frequently associated with the use of radiation to sterilize foods.

Hundreds of short-term and long-term safety studies led to the approval of one or more foods for irradiation by presently more than 60 countries. These studies are thoroughly reviewed in “The Safety and Nutritional Adequacy of Irradiated Foods,” published by the World Health Organization in 1994.

In the United States, the Food and Drug Administration reviewed the available studies for the quality of experimental design, rigor, and statistical validity before approving irradiation of a variety of food products including grain, fruits and vegetables, spices and dried herbs, meat and poultry, and eggs for human consumption.

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