THE FEDERAL LAWS that govern food safety are indeed cumbersome, confusing and inflexible, as was pointed out in a study released Friday by a committee of the National Academy of Sciences. But we are not persuaded that the committee is on the correct course with its proposed remedy of greater discretionary authority for the Food and Drug Administraton.

Our reservations have nothing to do with the performance or potential of FDA, which has experienced a remarkable rejuvenation under Commissioner Donald Kennedy. Rather, they arise from the fact that a virtue of the present system is that it responds to scientific uncertainties about safety by tending -- rather inflexibly, we concede -- in the direction of extreme caution. And this is not to be scoffed at, given the relatively primitive state of scientific understanding about carcinogenic and other toxic substances in the food supply. It is on that ground, then, that we find no reason to assume that the public well-being would be enhanced if the presnetsystem fo rigid prohibitons were replaced -- as the academy committee proposes -- by a system that would presume to balance riske against benefits.

If it were possible to achieve that balance with any degree of reliability, the case for increasing FDA's authority would be persuasive. But, as the committee itself points out, "With respect to many substances, analysts cannot determine with precison the degree of risk involved, and are even more uncertain in the assessment of benefits. Moreover, ther is great variation in both risks and benefits among various population groups."

Even more troublesome than this observation is a minority dissent that points out -- correctly, we believe -- that "there is no scientifically defensible way to divide carcinogens or other irreversible toxins into different risk categories."

Against this background of acknowledged scientific uncertainty, we see no justification for letting down the barriers. The saccharin controversy, which inspired a congressional request for the academy study, is a rather special and peculiar case that Congress has, at least temporarily, chosen to take away from FDA. But saccharin, given its popularity and the lack of an acceptable substitute, is quite possibly a one-of-a-kind case and ought not to be the trigger for generally reveamping the food-safety laws.

One point on which we wholeheartedly agree with the committee report concerns the need for enlarging our scientific knowledge of carcinogenesis and toxicity. Innumerable problems of food safety would simply dissolve if researchers possessed a fuller understanding of the biological complexities. When that's achieved, the basis for a discretionary approach will exist. Until then, there is considerable virtue in inflexibility.