Guest Column

Food Irradiation 101

by Michael T. Osterholm


With all the tough decisions that land on the desks of school leaders, should you add to the litany a concern about using irradiated foods in your school cafeteria?

Assuredly, no. Nearly every major science and health agency supports the consumption of irradiated food. These include highly reputable government agencies such as the World Health Organization and the Centers for Disease Control and Prevention and independent organizations such as the American Medical Association, the Council for Agricultural Science and Technology and the American Dietetic Association.

Irradiated ground beef became available to order through the U.S. Department of Agriculture's National School Lunch Program in January. While you probably are aware of the commodity offering, you may harbor questions about its merits. Beef is the only irradiated product offered to schools through the USDA.

Irradiation Benefits

Food irradiation uses high-energy radiation in any one of three approved forms: gamma ray, X-ray or electron beam. Gamma rays may be generated by two approved sources, either cobalt-60 or cesium-137. X-rays and electron beams are generated electrically by more powerful versions of the components found in televisions.

When ground beef is irradiated, at least 99.99 percent of Escherichia coli (E. coli) and many other harmful food-borne bacteria are killed, making the product safer for consumption. The CDC estimates roughly 73,000 cases of E. coli infection each year and 61 deaths, many of them children, in the United States. Many of these illnesses are associated with eating contaminated ground beef. Approximately 5 to 10 percent of school-aged children who are infected with E. coli will develop hemolytic uremic syndrome, the principal cause of kidney failure in children.

Statistically, there is a much greater threat from E. coli, salmonella and other pathogens than there is from bovine spongiform encephalopathy, better known as mad cow disease. E. coli, salmonella and other bacteria are killed with irradiation. Mad cow, a prion disease, is not.

The arguments against irradiation today are similar—and sometimes identical—to the argument waged decades ago against pasteurization. Opponents said it wouldn't prevent disease (it does), the taste was unpalatable (it's not) and it was an excuse for farmers to run a dirty operation (dairy farms are cleaner today than ever). At school, you would never consider serving raw, unpasteurized milk in the cafeteria because of the known risks. Those same risks exist with ground beef that has not been irradiated.

Food-borne illness outbreaks do happen in schools, sometimes despite the best efforts of the nutrition staff. A two-decade review shows that 600 such outbreaks have been reported. Nearly 1,500 kids required hospitalization and tragically one child died. Some of those outbreaks resulted from eating contaminated ground beef.

An elementary school in Washington state recently lost a $4.6 million lawsuit brought by the parents of 11 children who were sickened by consuming E. coli bacteria from contaminated, undercooked taco meat. Had that taco meat been irradiated, those children would not have gotten sick. A higher court upheld the ruling, dealing a harsh financial blow to the small school district.

A General Accounting Office report published in April 2002 estimates reported food-borne illness outbreaks in schools are increasing on average of 10 percent per year.

Irradiation provides an opportunity to decrease food-borne illness in schools. It is not a substitute for sanitary food processing and manufacturing, nor is it a substitute for good personal or kitchen hygiene.

Cafeteria Handling

Critics of irradiation contend it is unnecessary because bacteria are killed when meat is cooked properly. The problem is that many food preparers do not know proper cooking temperatures and some unfortunately do not follow safe food-handling practices. More than half of adult Americans who were randomly surveyed by the American Dietetic Association and ConAgra Foods did not know that ground beef should be cooked to 160 degrees Fahrenheit. In the same survey, only 5 percent used a meat thermometer to check the doneness of the food.

While school cafeterias employ staff members who likely have greater knowledge of food safety than the general public, a GAO report last May found nearly half of 40 large outbreaks at schools resulted from improper food preparation and handling practices in school kitchens. In the Washington state district involved in the multimillion dollar lawsuit over the E. coli outbreak, the ground beef was not cooked properly nor was it kept warm, according to Mary Ferluga, a state public health official who investigated. Ferluga said the food service employees in the school thought they were doing everything correctly.

Some schools have argued that irradiated ground beef is not an issue for them because their schools purchase precooked ground beef. That is not a safeguard against E. coli. When I was the state epidemiologist for Minnesota, I investigated a large E. coli outbreak (32 confirmed cases and 22 possible cases) that was ultimately traced to precooked hamburger patties served in a Twin Cities junior high school. The patties were not cooked sufficiently by the manufacturer and may not have been thawed or reheated correctly by the school.

Ferluga, now a food safety expert for Washington's public health department, believes irradiated ground beef should be served in schools. I agree.

This issue really is about children and their safety. It is not about the meat industry, lawsuits or activists. Nothing is more difficult than informing a parent that his or her child is gravely ill because of food the child ate. Imagine being a school administrator and having to tell a parent in private or admit in a court of law that a child's serious illness or death was linked to contaminated food served for lunch in the school cafeteria. The financial troubles eventually will go away, but the emotional pain may never fade.

Michael Osterholm, former state epidemiologist for Minnesota, is director for the Center for Infectious Disease Research and Policy, University of Minnesota, Mayo Memorial Building, MMC 263, 420 Delaware St., Minneapolis, MN 55455. E-mail: mto@umn.edu