The four major supermarket chains in the Boston area that claim they sell only United Farm Workers lettuce could not be doing so because there is not enough UFW lettuce available, a spokesman for A&P Food Stores national headquarters in New York charged yesterday.

A&P, the largest supermarket chain in the country, is the only major chain in the Boston area that has not made agreements to sell only UFW lettuce.

"I seriously dispute [the claims of the stores that they sell only UFW lettuce]. I could name you names, but that's not A&P's business. There is just not enough UFW lettuce to go around for them to carry it exclusively. Lettuce is not that identifiable, so it's easy to cheat," the spokesman said.

Al Sigman, the lawyer for the UFW in Boston, said yesterday that part of the UFW's agreements with the Boston stores includes the right to inspect their storerooms periodically.

"We know the stores sometimes cheat, but they don't do it for more than a couple of days when they can't get our lettuce," Sigman said.

Spokesmen for First National, Purity Supreme, Star Market, and Stop and Shop, the four chains with UFW pacts, all corroborated Sigman's statement yesterday.

The UFW currently controls about 15 per cent of the lettuce grown in the United States.