In the irradiation plant, food is exposed to thin rods of cobalt 60. The rods give off gamma rays, which disrupt chemical processes in contaminating organisms. The disruption breaks down the cell walls of organisms or destroys their genetic material. The dose, set by the U.S. Food and Drug Administration , is enough to kill organisms on food, but not enough to produce significant changes in the food itself.
Although irradiation slightly decreases the nutritive value of foods, the loss is less than that produced by some other methods of food preservation. Canning, for example, results in a much greater loss of nutrients.
Those who object to irradiation say that the process may create substances not found in nonirradiated food. Since the 1960s researchers have studied irradiated food at microscopic levels to try to find such substances, called unique radiolytic products. After reviewing these studies, the FDA determined that compounds formed during irradiation are similar to substance found in nonirradiated foods and are not dangerous to consume.
Destruction of microorganisms that cause illness is an important goal of irradiation. About 250 million cases of food poisoning or 1 per personoccur every year in the U.S., according to FDA estimates. Food poisoning can cause vomiting, diarrhea, fever, headacheand, occasionally, death.
Because of the apparent safety of food irradiation, and the problems presented by contaminated food, scientific groupsincluding the American Medical Association, the World Health Organization, and the United Nations food and Agriculture Associationhave voiced nearly universal support for the process. Worldwide, 38 nations have approved irradiation for 355 products.
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