US may allow use of gamma rays to help keep food fresh

Spread the table and contention will cease: So goes an old English proverb. But meat and vegetables themselves may soon be the center of controversy. Imminent changes in federal food and drug regulations may, for the first time in nearly 30 years, permit food irradiation - exposing fruit, vegetables, meats, and other foodstuffs to doses of ionizing radiation.

At very low levels, this technique can protect fruits, nuts, and vegetables against insects. Until now, this task largely fell to the chemical ethyl dibromide (EDB). But the chemical was banned recently by the Environmental Protection Agency.

At slightly higher dosages, irradiation retards spoilage and increases the shelf life of many foods. Irradiated produce stays fresh longer, and the technique's use with meats and canned food can drastically reduce the need for chemical preservatives such as salt and nitrite.

''For the consumer, this would have a number of health benefits. My only concern is public acceptance,'' says Manuel Lagunas-Solar, a scientist at the University of California at Davis, who has been experimenting for several years with radiation treatment of foods.

The process uses materials such as cesium - a waste product of nuclear reactors - as the source of radiation. Dr. Lagunas-Solar says he is worried that people will get the mistaken idea that the treatment will make food radioactive. Actually, the radiation levels being considered hardly effect the food: ''If it's done right, you can't see, smell, or taste any difference,'' he says.

The gamma radiation used is much like the microwaves used for cooking: It is pure energy. As such, it cannot leave any residue in food, unlike the chemical treatments it would replace. The radiation does cause chemical changes in food, however. For instance, it can tenderize tough meat. But none of the resultant chemicals differ from those created by cooking, canning, and traditional forms of food, Lagunas-Solar says.

Despite these facts, federal regulations have treated radiation as a food additive since the late 1950s. Because medical authorities have said that large amounts of radiation cause cancer, irradiation of food has been prohibited by the Delaney amendment, which banned the use of carcinogens as food additives.

The Food and Drug Administration recently drafted rules that would allow limited use of irradiation. These are currently under consideration by the Health and Human Services Department.

Irradiation is not cheap, says Niel Nielson, President of Emerging Technologies, a company waiting in the wings to build several irradiation plants once the government gives the green light. The treatment would add several cents per pound to the cost of food.

The impact on food prices of the widespread use of this process is uncertain. Mr. Nielson argues that the reduction in the post-harvest loss of produce would more than offset the price of the processing. The method could cut these losses in half, he says.

While agreeing with the potential for reduced losses, Lagunas-Solar is more skeptical that food distributors would pass these savings to the consumer.

Lagunas-Solar, who regularly irradiates potatoes he takes home, to retard sprouting, argues that the nation's 60,000 farm workers would receive the biggest benefit from the use of irradiation: Its use would drastically reduce their exposure to toxic chemicals like EDB.