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RADIATION

Food irradiation

A brief history of food irradiation
Food irradiation—the use of ionizing energy to kill bacteria, parasites and insects in food and to retard spoilage—is not new. Research began early in the 20th century in the United States and accelerated in 1953 as part of the government's "Atoms for Peace" effort.

In 1963, the U.S. Food and Drug Administration (FDA) began approving food irradiation—first to rid wheat and flour of insects and to control sprouting of potatoes. In 1983, the FDA approved irradiation of spices and seasonings, and in 1985 it approved irradiation to prevent trichinosis in pork. The following year, approval was extended to fruits and vegetables. In 1990, the FDA approved irradiation of poultry to prevent salmonella and other food-borne bacterial pathogens. And in December 1997, the agency approved its use for red meat to kill E. coli.

Next on the list of foods approved for irradiation may be fish and shellfish to kill salmonella, vibrio and other bacteria.

Widespread acceptance—Worldwide, more than 40 nations have approved the use of food irradiation. In addition to the United States, they include China, France, Germany, Great Britain, Israel, Japan, the Netherlands and South Africa.

The food irradiation process
The process exposes food to gamma rays from radioactive cobalt-60 (or, sometimes, electron beams and X-rays from accelerator machines).

During the process, prepackaged food is moved by conveyor into a thick-walled room housing the irradiator—pencil-like rods of cobalt-60. The food is exposed to the radioactive material for approximately 15 to 45 minutes, depending on the food. The fact that food is prepackaged eliminates the possibility that bacteria could be introduced after being irradiated. When the process is completed, the rods of cobalt-60 are retracted into a pool of water, which acts as a radiation barrier.

The same process has been used to sterilize medical devices, bandages, condoms, tampons, contact lens solution and food for astronauts.

The benefits of food irradiation
Irradiation is used in many nations to retard spoilage and increase the shelf life of food. This is particularly beneficial in areas lacking refrigeration. In addition, irradiation kills harmful bacteria that cause food-borne diseases, such as salmonella in poultry and some seafood, trichinosis in pork and cholera in fish.

The World Health Organization endorsed food irradiation in 1992, calling it a "perfectly sound food-preservation technology." The head of the group's food safety unit said irradiation is "badly needed in a world where food-borne diseases are on the increase and where between one-quarter and one-third of the global food supply is lost post-harvest." In September 1997, the World Health Organization again endorsed the use of food irradiation, and this time was joined by the United Nations Food and Agriculture Organization, and the International Atomic Energy Agency.

The ability of irradiation to rid food of harmful bacteria could reduce food-poisoning incidents. In the United States alone, according to the national Centers for Disease Control and Prevention, more than 33 million Americans become sick from food-related illnesses each year, and more than 9,000 die.

In early 1993, the U.S. Department of Agriculture advocated research on the benefits of irradiating ground beef, following a rash of deaths and illnesses caused by E. coli-tainted hamburgers from fast-food restaurants in Washington state and elsewhere.

Interest in irradiating ground beef resurfaced in mid-1997, after a Nebraska processing plant was forced to close and destroy 25 million pounds of meat possibly contaminated by E. coli. The U.S. Senate in September passed the FDA Modernization Act of 1997, which, according to the National Food Processors Association, would "advance the use of food irradiation as a food safety tool." In December, the FDA—after three years of limited activity on a petition to permit irradiation of beef—approved irradiation of red meat, including beef, lamb and pork.

Fourteen months later, the U.S. Department of Agriculture announced that it too would allow irradiation of red meat. While acknowledging that irradiation is "no silver bullet," Agriculture Secretary Dan Glickman said that its use on red meat could "provide consumers with an added measure of protection."

Health and safety issues
Irradiation does not make food radioactive. As a result, it does not increase human exposure to radiation. Extensive studies have yielded no conclusive evidence that eating irradiated foods is harmful in any way.

Irradiation has been found to reduce, in minimal amounts, certain vitamins in food. Particularly affected are vitamins A, C and E, and thiamin (vitamin B). Researchers have found, however, that the depletion generally is less than that caused by cooking, canning or freezing.

Molecular Shuffle—One of the most frequently raised issues involving irradiation is whether the process forms toxic radiolytic products by rearranging the molecular makeup of certain foods. Some foods contain naturally occurring radiolytic products—benzene and formaldehyde, for example. Other radiolytic products are produced, for instance, when meats are grilled over a fire. Opponents of irradiation claim that unique radiolytic products are formed during exposure to the gamma rays. They contend that unique radiolytic products, whose health effects are unknown, could be harmful. Extensive studies, however, have identified no radiolytic products unique to irradiated foods, and none that suggest harm.

Irradiated food sold in stores in the United States must, according to federal law, be identified with the green, flowerlike international symbol for irradiation. Labeling also must include the words "Treated with Radiation" or "Treated by Irradiation." However, since the federal government lacks jurisdiction over establishments selling prepared foods, irradiated foods could be served without such labeling. In addition, irradiated ingredients need not be identified as such on labels of prepared and processed foods.

Public opinion
Consumer surveys show mixed reactions to food irradiation. The October 1989 issue of Food Technology magazine reported that Americans are more concerned about chemical sprays, pesticide residues, preservatives and food-borne diseases than about food irradiation.

In 1990, the U.S. General Accounting Office studied the bans on irradiated foods in Maine, New Jersey and New York. Its report said: "Officials of those states told us that their states took the actions in response to public concern by citizen groups rather than as a result of scientific evidence questioning the safety of food irradiation."

A 1993 study by Purdue University found that people's attitudes about irradiation improved markedly after they learned about the science behind the technology. In the study, two groups of adults were shown a seven-minute educational video on food irradiation, and polled before and after. One group's acceptance of food irradiation grew from 54 percent to 90 percent; the other improved from 69 percent to 99 percent.