LED BY the National Soft Drink Association and the American Meat Institute, the food industry is pushing for a sweeping revision of the food safety laws. Consumer groups are opposing what the industry is proposing, and congressional staff members are receiving an endless stream of lawyers, lobbyists and regulators. Yet, oddly, as the sides prepare for a battle, there seems to be general agreement among those who know it best that the law, as applied by the Food and Drug Administration and interpreted by the courts, has on the whole worked pretty well.

The food supply, it turns out, is not as relatively uncomplicated a thing as it might seem. Food additives, for example, are not just substances like preservatives, coloring agents, emulsifiers and so forth that are deliberately added to food. There are substances "added" to the food supply while it is growing: animal drugs and hormones in meat, for example. There are also toxic substances that may migrate into food from its packaging: lead from cans, for instance. And there are natural or man-made contaminants, such as pesticides, PCBs and mercury, that enter the food supply from the general environment. To top it all, naturally occurring foods and all their individual components are themselves considered to be additives when they, or their components, become part of processed foods--peanuts in peanut butter, for instance, or nutmeg in eggnog.

This broad legal definition of a food additive accounts for much of the opposition to the controversial Delaney clause that bans the use of additives found to cause cancer in human beings and animals. As it becomes harder and harder to define what "causes" cancer--scientists now distinguish, for example, between direct carcinogens, cocarcinogens, promoters and more--and as rapidly advancing technology provides the capacity to detect substances present in infinitesimally small amounts, the 20-year-old Delaney amendment appears to be out of step with current knowledge.

No one, however, has come up with a good substitute. The food industry's suggestion that only substances shown to present "significant risks to health" be banned is premature: there are not yet agreed methods for calculating such risks or for determining which among them is significant. It is an invitation to endless litigation. It would, for example, allow the use of inessential additives such as coloring agents--even after they had been shown to be carcinogenic in animals.

Moreover in only two cases--saccharin and nitrites--has the Delaney clause actually created much controversy. Both of these could have been accommodated by relatively minor changes allowing the FDA some flexibility--such as a phase-out while alternatives are sought rather than an immediate ban--in cases where an additive provides a clear benefit to consumers.

In the coming debate, the burden should be on those who propose changes to demonstrate just where the current law does not work. Are there, for example, additives or substances that should be on the market that the current law does not allow to be sold? Americans now enjoy the world's most varied, and probably its safest, food supply. Congress shouldn't act unless it is sure it is making things better.