Gamma Burgers

Gamma Burgers

Gamma Burgers

Health and medicine explained.
Sept. 12 1997 3:30 AM

Gamma Burgers

Food irradiation is safe, even if it is overkill.

I pretty much ignored the first reports this summer that people were getting food poisoning from E. coli O157:H7 bacteria in hamburgers. I might have raised an eyebrow when beef supplier Hudson Foods recalled 25 million pounds of hamburger. But when the recall caused Burger King to run out of burgers, I started to worry. Shouldn't somebody do something about this food poisoning thing?


The Big Media apparently agreed. Within days of the recall, the New York Times, the Wall Street Journal, Newsweek, and others were proposing a simple solution: Irradiation of food to kill not just E. coli but all the nasty germs and parasites that slip into our food supply.

This rapid blanket approval of irradiation by the establishment naturally stirred my suspicions. We are talking about radioactivity, after all. On closer inspection, however, food irradiation turns out to work safely and effectively, opponents' concerns notwithstanding. But questions remain about whether food poisoning is such a big problem in the first place.

Human skin and intestines crawl with ordinary E. coli. But a few uncommon strains of the bacteria--especially the notorious E. coli O157:H7--produce toxins. Ingest these toxic bacteria, and you experience watery diarrhea and severe abdominal pain at first, bloody stools next. You're miserable, but these symptoms don't usually require medical attention--at least, in developed countries. But in some cases, the toxins trigger the destruction of blood cells and cause renal failure. This "hemolytic uremic syndrome" can be deadly in children. The Centers for Disease Control estimate that toxic E. coli cause 25,000 cases of illness and up to 100 deaths each year in the United States.

Meat is the most common source of E. coli O157:H7, but raw milk, vegetables, and fruit juice have carried it in recent outbreaks. (You may recall that toxic E. coli showed up in alfalfa sprouts two months ago, and in Odwalla apple juice last year.) The bug lives in the guts of about 1 percent of cattle and contaminates meat when digestive contents spill where they shouldn't during slaughter. It also contaminates produce if farm waste-water enters the irrigation supply. Toxic E. coli are just one of the top seven bacterial food contaminants. More common bacteria, such as salmonella (present in 60 percent of chicken) and campylobacter (the number one cause of food poisoning), cause diarrhea for 2 million to 4 million Americans each year. However, washing your produce and cooking your meat until well done will almost always remove these bacteria.


Burger King terminated its Hudson Foods supply contract not for safety concerns but for PR reasons. Like other fast-food chains, it cooks its burgers to over 155 degrees, killing all bacteria. But it feared that it might earn a reputation for bacteria burgers, which has plagued the Jack in the Box chain ever since 1992, when four people ate some of its undercooked, tainted beef and died. (Ironically, Hudson Foods, primarily chicken suppliers, didn't distribute beef until Burger King talked them into the business a few years ago.)

Advocates of food irradiation say that a rare burger doesn't have to be dangerous. Irradiators containing cobalt-60 or another radioactive source would bombard hamburger, apple juice, and other foods with gamma rays, killing resident bacteria and parasites. The radiation disrupts DNA, which germs need to survive. (Meat doesn't need functional DNA, since it's already dead.) Lower doses will pasteurize food--i.e., kill the disease-causing organisms. Higher doses of radiation will completely sterilize food.

Supporters of irradiation like writer Richard Rhodes argue that the process is perfectly safe, leaves no funny taste or appearance, and prevents illness from E. coli O157:H7, salmonella, beef tapeworms, fish parasites, and trichinae in pork. Since fungi are killed, radiation-pasteurized food lasts longer, too--up to two weeks in the fridge instead of a few days. For gamma ray fans, food irradiation is the most logical step after heat pasteurization of milk.

The Food and Drug Administration has approved irradiation of produce, pork, poultry, and other foods, but industry has not adopted it widely. (For unclear reasons, the FDA has stalled on a 1994 application to allow the industry to irradiate beef and veal.) You'd think that the poultry industry, which has suffered terrible publicity over salmonella outbreaks, would rush to irradiation, but it fears that the negative public reaction to irradiation would be worse. Currently, astronauts, patients in many hospitals, and people in 27 other countries eat irradiated food.

Illustration by Whiting Tennis

Advocates blame slow adoption of irradiation on technophobic lobbying groups that ignore the evidence and stir public fears with outrageous claims that the process makes food radioactive. The critics I spoke to, however, offered credible arguments. Most admit that irradiation works, and some, like Michael Jacobson of the Center for Science in the Public Interest, will even concede it's safe for consumers. But they argue that it's expensive, harmful to workers and the environment, and unnecessary if safer farming methods are practiced. They suggest growing livestock under cleaner, less confined conditions to prevent contamination of feed and water; slaughtering the animals so bacteria-containing skin and feces never get on food; and using simpler technologies, like steaming, to clean raw meat. As environmental advocate Michael Colby told reporters, "Irradiation is a cop-out. Irradiation is saying we have to have fecal matter in our hamburgers."

For the record, gamma rays do not make food radioactive. And studies do seem to show it's safe. In a six-year study, scientists fed dogs and other animals irradiated chicken and found no evidence of increased cancer or other toxic effects. Other research found no signs of hazard in humans who eat irradiated food. Also, studies showed that, at the lower, pasteurization doses, radiation does not degrade nutrients. The World Health Organization, the American Medical Association, and the American Dietetic Association all back the technology as safe.

What about the other arguments against irradiation? It doesn't seem expensive--they use it in Bangladesh, after all. A Florida company charges 4 cents a pound for irradiation, and advocates say wider use would halve costs. The risks to the environment and to workers seem theoretical. The same technology is already used safely in hospital radiation-therapy units and plants that sterilize medical products. Food irradiators do produce radioactive waste that must be stored under nuclear regulatory guidelines, but the current regulations governing hospitals and sterilization companies seem to work, and the amount of radwaste generated is far too small to cause Three Mile Island-like effects. Advocates like to point out that the waste hasn't killed anyone, but kids die every year from food poisoning.

Irradiation also seems more cost-effective than changing farming and slaughtering practices. It's pretty hard to keep feces out of meat. Some meat producers in Sweden do, but their meat is double or even triple the usual price. And even with clean practices and technologies like steaming of meat (which hasn't been tested nearly as much), some food would still be contaminated. Advocates say there'd still be reason to irradiate.

So irradiating food seems safe, effective, and cheap. Yet it also seems like a high-tech swatter for an overhyped fly. Toxic E. coli infect just three in 100,000 people. Thanks to officials who pushed for a recall, Hudson hamburgers didn't kill anyone. Irradiation backers exaggerate food poisoning's impact, claiming the top seven contaminants kill 9,000 people each year. According to the most recent data, though, fewer than 1,000 people die from tainted food each year. Compare that with, say, car accidents, which kill 40,000 people a year, or smoking, which kills over 400,000.

Food poisoning is a serious risk only for vulnerable populations, like the very young. For the rest of us, it's an uncommon annoyance caused mainly by inadequately cooked chicken or pork. I'm not against saving a few hundred lives a year for a few pennies extra on my beef, so go ahead and zap my food. But irradiated or not, I'll still order my burgers rare.