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One old idea The idea of blasting bacteria with radiation was raised shortly after 1895, the year X-rays were discovered. During World War II, the U.S. Army irradiated meat to extend its life in rations, and in 1963 the Food and Drug Administration approved irradiating wheat and wheat flour. In the ensuing years the agency has permitted the zapping of spices, fruit, pork, vegetables and poultry. The process can kill bacteria, fungi and parasites in food.
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Food takes its lonely trip through the irradiator hanging from a ceiling track. Concrete walls and corners trap gamma rays. Food does not get radioactive, any more than your teeth glow after a dental X-ray. Courtesy of Isomedix, Inc.
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The zappers won't start blasting red meat right away, since the U.S. Agriculture Department must still approve the procedure. "The Food and Drug Administration's rule on irradiation of meat recognizes the safety and effectiveness of irradiation in reducing pathogens in meat products," said Catherine Wotaki, undersecretary for food safety. "USDA places a high priority on the preparation of a final rule for the irradiation of meat to reduce pathogens." The regulation could be law by next summer.
Yet "legal" may not equal "desirable." Poultry irradiation was OK'd in 1992. So why is virtually nobody selling irradiated birds? "That's a market determination," says Jacque Knight of the Food Safety Education and Communications Staff at the U.S. Department of Agriculture. "The market is not there, nobody's been advertising irradiated poultry. [The same thing] could happen with beef, but the ball will be in the industry's court to advertise it."
Howzit work?
Not exactly. Food is irradiated in buildings like the ones used to sterilize medical equipment and consumer products. Automated trolleys carry the food past a stationary radiation source. Since rays can't sneak around corners, a combination of corners and massive concrete walls contain the radiation. Controlling the dose is as simple as adjusting the speed of the trolley. When the irradiator is idle, the radioactive rod containing the cobalt-60 is dunked into a ray-proof water bath. Gamma rays are extremely energetic electromagnetic waves produced in some radioactive decays. Unlike the neutrons made during decay at nuclear electric generators, gamma rays can neither start a chain reaction nor make anything radioactive. Most of that dose zips right through the food, just as most dental X-rays zip right through your body. The gamma rays that are intercepted provide the energy to kill pathogens by destroying their DNA, and are particularly potent in targeting cells that are dividing, which many microbes are doing when they first enter food. (Small doses of radiation also damage DNA, says Timothy Strane, a nuclear pharmacist at St. Luke's Medical Center in Milwaukee, Wis., but organisms usually survive because they have time to repair the damage.) If you see irradiated food as a cut-rate disposal for radioactive waste, Grace Masefield, Isomedix's director of marketing, says the company's cobalt-60 is custom-made at a reactor in Ontario. She adds that cobalt 60 forms stable (non-radioactive) elements when it decays, and thus does not produce any radioactive waste of its own. We've been stalling on the big question. What does it do to the grub? |
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