The technology of preserving food with ionizing radiation has been around for more than four decades, and most experts are convinced that the safety issues were resolved years ago. The method is approved in 38 countries. In the U.S, irradiated poultry, pork, fresh fruit and spices can be sold. But not beef.

In July 1994 Isomedix Inc., an irradiation-equipment manufacturer based in Whippany, NJ. asked the Food and Drug Administration to approve irradiation for beef. The FDA has been "considering" the application ever since.

Three years ago, the meat industry took little notice of the petition--because there was vocal opposition to irradiation, and consumer acceptance was in question. Now, meat processors are struggling with devastating recalls of beef contaminated with new and more virulent foodborne pathogens, such as E. coli O157:H7 and campylobacter. And they are facing a push in Congress to toughen regulatory controls over food processors.

These days irradiation looks like the one relatively inexpensive technology that will allow beef packers to assure the safety of their products--and it appears that a public now more fearful of tainted food than radiation may accept it. "If I had a crystal ball that could predict the future, I'd say the Hudson hamburger incident may lead to consumer acceptance of irradiation," says Richard Linton, a Purdue University Cooperative Extension Service specialist in food safety.

So, the cattlemen have now thrown their weight behind Isomedix. "For over three years, the meat industry has been assured that the irradiation petition is moving forward within FDA," wrote J. Patrick Boyle, president of the American Meat Institute in a September letter to FDA Deputy Commissioner Michael Friedman. "In the wake of the recent, highly publicized outbreak of foodborne illness linked to E. coli O157:H7, we are compelled to ask: What is delaying this important petition? As FDA knows, it is a petition for use of technology with the literal potential to save lives."

Ironically, the irradiation process was developed with that very objective. Because an Army runs on its stomach--and must be supplied with nutritious provisions in some pretty difficult situations--the military has been a major source of research in food preservation and packaging. During the Atoms for Peace program of the 1950s, U.S. Army researchers came up with the idea of zapping food with radiation to render it completely sterile. Today soldiers in combat and space shuttle astronauts routinely feast on irradiated steaks.

Irradiation works by stripping electrons from atoms to create positively and negatively charged ions that harm or kill rapidly growing cells in molds, fungi, insects and microbes. Sources of the radiation are metallic gamma-ray emitters, such as cesium-137 or cobalt-60; electron beams and x-rays can produce the same effect. The process does not leave residual radiation or make the treated food radioactive.

The effect of irradiation depends on the dose. In 1965, studies by the Office of the Surgeon General of the United States Army concluded that foods irradiated with doses up to 56 kilograys were safe to eat. At very high exposures, food is sterilized and, if the packaging remains intact, it can be stored without refrigeration almost indefinitely, such as the meat provided to astronauts.

The beef producers are asking to irradiate their products at 4.5 kilograys. This dose provides an effect similar to pasteurization. Refrigeration is still required, but shelf life is extended and pathogens such as E. coli are destroyed. At lower levels, insects and their larvae are killed and the ripening of fruits and vegetables is delayed. Because the process does not involve heat (in fact, it can be used to treat food that is already frozen), the nutritional value of irradiated products is not reduced, although some studies have reported the loss of some vitamins at high radiation levels.