Calgene voluntarily submitted data on the tomato for Government scrutiny, even though it is not required to do so, because it wanted the F.D.A.'s safety endorsement.

But the approval of Flavr Savr rallied opposition.

Douglas Hopkins, a senior lawyer with the Environmental Defense Fund, said approval of the tomato would be an exception rather than the rule. He said most other genetically engineered food products would not get approval of F.D.A. nor would they require any special labeling.

"What we have is a purely voluntary system where it is up to the companies to decide if a new food product is safe or substantially different from older foods to be reviewed," Mr. Hopkins said. "Genetically engineered foods represent time bombs that the F.D.A. can defuse easily by changing its policy."

Mr. Rifkin of the Pure Food Campaign, which has long opposed introducing genetically altered food products, said such products should be labeled in the store as "genetically engineered" or a result of "gene splicing" so consumers could make a choice about using them.

The group, which is based in Washington but has chapters nationwide, will picket markets, hand out notices to consumers and organize "tomato dumpings" and boycotts wherever the Calgene tomato is sold to protest the product, Mr. Rifkin said. He said the group would file suit in Federal court challenging the F.D.A.'s approval of the tomato and its decision not to require special labeling so that consumers would know its origin.

Richard M. Kessel, executive director of the New York State Consumer Protection Board, also criticized the Government's approval of the tomato without requiring labeling that would identify it. He said he would petition the Federal agency to require labeling of biologically engineered products.

"It is absolutely unconscionable that within 10 days of the F.D.A.'s enactment of their much publicized new food labeling regulations, it would permit the entrance of an entirely new product manufactured through the use of genetic engineering without disclosing this fact to consumers," he said. Labeling by Product Reaction