Physics

The Dangers of Radioactivity



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Food Irradiation

Although irradiation has been approved for use on certain foods in the U.S. for more than 40 years, the FDA's recent authorization for irradiating red meats has brought this issue to the forefront of the industry agenda. NCBA supported the action by FDA and, at the Centennial Convention in February, passed a resolution

o to encourage implementation of irradiation technology

o to encourage USDA to develop and implement rule-making to allow use of this technology

o to educate consumers, food service groups, retailers, and producers about irradiation

o to establish consistent terminology for this technology

Food irradiation is the exposure of food to low doses of gamma rays, x-rays, or electrons to destroy pathogenic foodborne bacteria and parasitic organisms. Because the results are similar to pasteurization, but without using heat, irradiation is sometimes referred to as "cold pasteurization" or "ionizing pasteurization." The term "ionizing" means that this form of radiation has sufficient energy to create positive and negative charges, leading to the death of bacteria and other pathogens on food.

The FDA has previously approved three types of irradiation for the treatment of foods:

o gamma rays produced by natural decay of radioactive isotopes of cobalt-60 or cesium-137;

o x-rays with a maximum energy of 5 million electron volts (MeV); and

o electrons with a maximum energy of 10 MeV.

One electron volt (eV) is the amount of energy acquired by an electron when it is accelerated by one volt in a vacuum. USDA currently is establishing irradiation specifications for beef.
The level of energy used for food irradiation affects only live organisms such as bacteria, insects, and protozoa that may be present, significantly reducing the chances of foodborne illness. Because harvested meat is no longer "living," there is very little effect on the meat's appearance, taste, or nutritive value. The food never touches a radioactive substance; therefore, it does not retain any energy waves or radioactive residues.

Irradiation extends the shelf life of certain fresh foods by attacking the proteins that regulate ripening, aging, and spoiling; thereby inhibiting sprouting and mold growth. This means irradiated fruits and vegetables can be picked vine-ripe and still be fresh, nutritious, and colorful when marketed.

Irradiation was previously approved in the U.S. for spices, fruits, grains, vegetables, pork (trichina control), and poultry. A petition to irradiate seafood is pending. The technology is more commonly used outside the U.S. Irradiated foods are commercially available in 28 countries.

The technology has been endorsed as a method of enhancing food safety by FDA, USDA, U.S. Department of Health and Human Services, U.S. Public Health Service, U.S.
Army, National Association of State Departments of Agriculture, the American Medical Association, the American Dietetic Association, and the Institute of Food Technologists. In addition, the United Nations Food and Agricultural Organization, the World Health Organization, and the Codex Alimentarius Commission support the use of irradiation to preserve the wholesomeness of food.

Where are we now?

Currently there are about 40 irradiation facilities in the U.S., mostly for medical instruments and supplies such as intravenous fluids, gowns, and drugs. Certain consumer items also are irradiated such as contact lenses, cookware, and baby products. Although some universities are testing various types of food irradiators, there are few facilities in the U.S. approved for commercial food irradiation. The Nuclear Regulatory Commission oversees the construction and operation of all irradiation facilities.

USDA is now preparing proposed rules for irradiating red meats. These rules will cover procedural details such as temperatures, dosage, and record-keeping and labeling requirements. The National Food Processors Association (NFPA) has petitioned USDA to eliminate the requirement for irradiated food to carry the "radura" symbol and label statement. NFPA believes this labeling is unwarranted for a technology that has been proved safe, and fears consumers might view it as a message of warning rather than reassurance.

Once the rules are written and published, there is a public comment period followed by a response by USDA. When all of the federal regulations are in place, consumer acceptance and demand will largely determine the speed with which irradiated food products will be available to consumers.

Key Facts

o Each of the FDA-approved types of ionizing radiation for foods-gamma rays, x-rays, and electron beam-has advantages and disadvantages such as efficiency, penetration of the food item, processing speed, and cost of construction and operation of the facility.

o The radiation dose can be varied depending on the desired results. Relatively low doses are sufficient to control foodborne pathogens and preserve freshness. (Foods irradiated at this level are not sterile; therefore they must be properly refrigerated, handled, and cooked the same as non-irradiated foods.) Higher doses of radiation can sterilize foods for specific purposes, such as for astronauts and for patients in nursing homes and hospitals whose immune systems are weakened.

o Food can be irradiated when fresh or frozen, whole or packaged.

o The increased cost for irradiated ground beef is estimated to be about 1 to 5 cents/lb. Benefits to retailers and consumers may offset this cost.

According to Food Technology magazine, "When informed of the benefits of irradiation, consumers are willing to purchase irradiated foods, even at higher cost." Retailers also benefit from reduced spoilage and reduced liability risk.

In various test markets and in the four U.S. retail stores that continuously offer irradiated foods, consumer acceptance has been high, particularly when education on the technology precedes the supermarket choices.

Sterilization by irradiation would have saved innumerable consumers who otherwise died of various viruses.

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