Food irradiation
Food irradiation is a process that utilizes nuclear radiation to sterilize and preserve food, aimed at reducing spoilage and the risk of foodborne illnesses. The technology, which has been studied since the 1950s, has received approval from the U.S. Food and Drug Administration (FDA) for various food items, including fruits, vegetables, fish, and meats. Proponents argue that irradiation effectively extends shelf life and eliminates harmful microorganisms without making the food radioactive. Common sources of radiation include cobalt-60, which is used in controlled environments to irradiate food packages.
Despite its benefits, food irradiation is met with skepticism from some segments of the public, who raise concerns about the broader implications of nuclear technology, including safety issues related to the handling and disposal of radioactive materials. Critics often link fears of nuclear hazards to food safety, despite evidence suggesting that irradiated foods do not pose additional health risks compared to non-irradiated counterparts. Regulatory bodies like the World Health Organization and the American Medical Association endorse food irradiation, yet consumer choice remains paramount, with labeling requirements such as the Radura symbol informing individuals about the treatment of their food.
Subject Terms
Food irradiation
DEFINITION: A process in which nuclear radiation is used to sterilize foods
Although many studies since the 1950s have concluded that the irradiation of food poses no danger to those who consume the food, the process is still the subject of some debate.
Food is used to reduce spoilage of food and to decrease the incidence of illness from contaminated food. The U.S. Food and Drug Administration (FDA) has certified that irradiation is safe for many foods, including spices, fresh fruit, fish, poultry, and hamburger meat. Opponents of food irradiation focus on the inherent hazards of nuclear technology—particularly the production, transportation, and disposal of radioactive materials—and criticize the possible creation of harmful products in foods.
The most common radioactive source used for food processing is cobalt 60, which is produced through the irradiation of ordinary cobalt metal in a nuclear reactor. The shape of the source is typically a bundle of many thin tubes mounted in a rack. The source is kept in a building with thick walls and under 4.6 meters (15 feet) of water for shielding. The food to be irradiated is packaged and put on a conveyor belt. The operator raises the cobalt-60 source out of the water by remote control as the food packages slowly travel past the source on the moving belt. Typical time ranges from three to thirty minutes, depending on the type of food, the required dose, and the source intensity. Radiation dose is measured in a unit called the kilogray (kGy), where one kGy equals 1,000 Grays, and one Gray equals 100 radiation absorbed doses (rads). (The Gray is named for British radiation biologist Louis Harold Gray. The rad is an older unit still commonly used in the medical profession.) When radiation passes through the food, it interacts with atomic electrons and breaks chemical bonds. Microorganisms that cause food spoilage or illnesses are inactivated, so they cannot reproduce.
Fresh strawberries, sweet cherries, and tomatoes have a normal shelf life of only seven to ten days. Research has shown that a radiation dose of 2 kGy can double the shelf life of these fruits without affecting the flavor. Trichinosis parasites in fresh pork can be controlled with a dose of 1 kGy. Doses up to 3 kGy are used to destroy 99.9 percent of salmonella in chicken meat and Escherichia coli in ground hamburger. A dose of less than 0.1 kGy is sufficient to interrupt cell growth in onions and potatoes to prevent undesirable sprouting in the spring. Larger doses, up to 30 kGy, are used to eliminate insects, mites, and other pests in spices, herbs, and tea. The American Dietetic Association supports food irradiation as an effective technique to reduce outbreaks of food-borne illnesses.
Studies of Irradiation Effects
Irradiated food does not become radioactive. It does not “glow in the dark,” as some opponents of irradiation have claimed. Hundreds of animal feeding studies with irradiated foods have been done since the late 1950s. Irradiated chicken, wheat, oranges, and other foods have been fed to four generations of mice, three generations of beagles, and thousands of rats and monkeys. No increases in cancer or other inherited diseases have been detected in comparison to control groups eating nonirradiated food. In one experiment, several thousand mice were fed nothing but irradiated food. After sixty generations—about ten years—the cancer rate for the experimental group was no greater than for the control group.
In studies looking for potentially harmful by-products from radiation, chemical analyses of irradiated foods have found small quantities of benzene and formaldehyde. However, canning, cooking, and baking have been shown to create these same by-products even more abundantly. Based on the accumulated evidence, food irradiation has been endorsed by an impressive list of organizations: the American Medical Association, the U.S. Department of Agriculture, the American Diabetic Association, the World Health Organization, the United Nations Food and Agriculture Organization, and the FDA. Astronauts on space missions have eaten irradiated foods since 1972, and many hospitals use irradiated foods for patients with impaired immune systems.
Opposition to Irradiation
The antinuclear movement was born after World War II when the United States and the Soviet Union were conducting nuclear weapons tests that released large amounts of radioactive into the atmosphere. Public pressure eventually led to the Limited Test Ban Treaty in 1963. Three serious accidents at nuclear power plants, one at Three Mile Island (1979) in the United States, one at Chernobyl (1986) in the Soviet Union, and another in 2011 at Japan's Fukushima Daiichi nuclear power plant, dramatized the hazards of nuclear technology for the general public. In its literature, a consumer activist organization called Food and Water, based in Walden, Vermont, connects fear of the atomic bomb with food irradiation by showing a picture of a mushroom cloud hovering over a plate filled with food. The caption says, “The Department of Energy has a solution to the problem of radioactive waste. You’re going to eat it.” The most serious safety issues relating to food irradiation lie in the production of radioactive cobalt; in the protection of workers who transport, install, and use the source; and in the eventual disposal of radioactive waste. Such issues, however, do not have the same impact on consumers as the implied claim that foods may become tainted by irradiation. Commercial food processors have been deterred from installing irradiation facilities by fear of negative publicity and a potential consumer backlash.
The FDA requires that irradiated foods packaged for sale in the United States be labeled with a special symbol (the Radura) and the statement “treated with radiation.” It is up to consumers to decide if the benefits of a safer food supply outweigh the potential hazards of an expanded nuclear industry.
Bibliography
"Food Irradiation: What You Need to Know." Food and Drug Administration, 5 Mar. 2024, www.fda.gov/food/buy-store-serve-safe-food/food-irradiation-what-you-need-know. Accessed 17 July 2024.
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Hilgenkamp, Kathryn. “Food Safety Concerns.” In Environmental Health: Ecological Perspectives. Sudbury, Mass.: Jones and Bartlett, 2006.
Louria, Donald B., and George G. Giddings. “Point-Counterpoint: Controversy over Food Irradiation.” In Human Biology, by Daniel D. Chiras. 9th ed. Sudbury, Mass.: Jones and Bartlett, 2018.
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Wood, Olivia Bennett, and Christine M. Bruhn. “Position of the American Dietetic Association: Food Irradiation.” Journal of the American Dietetic Association 100, no. 2 (2000): 246-253.