Irradiation of food
July 22, 2004
New England Journal of Medicine: Vol. 351, No. 4

Michael McCally, M.D., Ph.D., of the Mount Sinai School of Medicine, New York, NY, and Martin Donohoe, M.D., Portland State University, Portland, OR, write in this letter that both the Sounding Board article by Osterholm and Norgan and the Perspective article by Thayer (April 29 issue)1,2 call for greatly expanded use of irradiation to prevent foodborne illness. The authors, two of whom receive funding from the food-irradiation industry, mention but dismiss strong arguments against the use of this technology.

The authors say in the letter that many studies have shown that irradiated foods, which contain novel carcinogens called 2-alkylcyclobutanones (2-ACBs), have a worse taste and have potential adverse health consequences.3 The European Union recently voted to deny a permit for the expanded use of food irradiation, pending further study of 2-ACBs.

A majority of Americans oppose food irradiation, which adds considerably to the cost of food. Some school districts have adopted policies prohibiting irradiated food.4 Many costly, new nuclear processing facilities containing highly radioactive sources would be required, raising issues of worker safety, transportation safety, the disposal of radioactive waste, and possible targets for terrorism. No research shows the effectiveness of food irradiation. Does food irradiation reduce the incidence of foodborne illness in the community and improve the outcomes of such illness? Given safer, cheaper, and more effective alternatives to ensure food safety,5 large-scale food irradiation should not proceed without further study, including a demonstration of its effectiveness.

References
1.Osterholm MT, Norgan AP. The role of irradiation in food safety. N Engl J Med 2004;350:1898-1901.[Full Text]
2.Thayer DW. Irradiation of food -- helping to ensure food safety. N Engl J Med 2004;350:1811-1812.[Full Text]
3.Raul F, Gosse F, Dilincee H, et al. Food-borne radiolytic compounds (2-alkylcyclobutanones) may promote experimental colon carcinogenesis. Nutr Cancer 2002;44:189-191.[CrossRef][Medline]
4.Burros M. Irradiated beef: a question in lunchrooms. New York Times. January 29, 2003.
5.Nestle M. Safe food: bacteria, biotechnology, and bioterrorism. Berkeley: University of California Press, 2003.

Dr. Osterholm and Mr. Norgan of the University of Minnesota reply that the comments of McCally and Donohoe reflect what they consider to be the emotional effort of a few to provide misinformation against the use of irradiation that would dramatically improve the safety of segments of our food supply. Their concerns are factually incorrect, extraneous to a discussion of the safety of irradiation, or directly refuted by scientific data cited in the article.

Osterholm and Norgan write that every major scientific and medical organization in the world that has evaluated food-irradiation technology has endorsed its safety. The legislation that authorizes the approval process for food irradiation precludes approval on the basis of a riskbenefit analysis (i.e., the benefit of food irradiation in preventing morbidity and mortality that are related to foodborne diseases vs. the risk of an adverse health consequence from consuming irradiated food). Rather, to be approved, food irradiation must meet the more stringent "no detectable adverse health consequence" standard. The fact that applications for the irradiation of a variety of foods have been approved by the Food and Drug Administration indicates the current medical and scientific consensus on the issue.

Dr. Thayer of Lower Gwynedd, PA replies that McCally and Donohoe ignore the results of a multigeneration, multispecies feeding study in which 135,406 kg of chicken sterilized by irradiation provided 35 percent of the diet for test animals: no treatment-related abnormalities or changes in the test animals were detected.1 The European Commission's Scientific Committee on Food concluded in July 2002 that genotoxicity of 2-ACBs had not been demonstrated. The commission's conclusion is supported by animal-feeding studies,1 lack of mutagenicity of 2-dodecylcyclobutanone,2,3 and routine use of irradiated feeds to ensure that the test animals remain disease-free during toxicology studies. Evaluation of many generations of test animals that have consumed diets consisting of irradiated foods would be expected to reveal any long-term effects, yet the animals breed normally and show no signs of genetic, teratogenic, or other abnormalities.4 The effectiveness of irradiation in killing foodborne pathogens such as salmonella, Listeria monocytogenes, Escherichia coli O157:H7, and Staphylococcus aureus in meat and poultry is well documented,5 and there have been no recalls of irradiated hamburger or poultry due to contamination. Food irradiation neither uses nor generates nuclear waste.

References
1.Thayer DW, Christopher JP, Campbell LA, et al. Toxicology studies of irradiation-sterilized chicken. J Food Prot 1987;50:287-288.
2.Sommers CH. 2-Dodecylcyclobutanone does not induce mutations in the Escherichia coli tryptophan reverse mutation assay. J Agric Food Chem 2003;51:6367-6370.[CrossRef][ISI][Medline]
3.Sommers CH, Schiestl RH. 2-Dodecylcyclobutanone does not induce mutations in the salmonella mutagenicity test or intrachromosomal recombination in Saccharomyces cerevisiae. J Food Prot 2004;67:1293-1298.[ISI][Medline]
4.Swallow AJ. Wholesomeness and safety of irradiated foods. In: Friedman M, ed. Nutritional and toxicological consequences of food processing. New York: Plenum Press, 1991.
5.Thayer DW, Boyd G, Fox JB Jr, et al. Variations in radiation sensitivity of foodborne pathogens associated with the suspending meat. J Food Sci 1995;60:63-67.[ISI]