Israel Cohen, the 72-year-old chairman of Giant Food Inc., sold a $6 million block of stock this week but denied once again that the company is for sale.

The majority of the stock sold -- 252,000 shares -- was sold yesterday just prior to Giant's annual meeting, over which Cohen presided.

Cohen said earlier this summer he planned to sell the stock to purchase a condominium in Chevy Chase and to raise "some cash to operate in the style to which I've become accustomed." Cohen still owns 1.4 million shares of non-voting stock, worth more than $33 million, and about 4.6 percent of Giant's total non-voting shares.

Giant stock, which split 2 for 1 last June, closed yesterday at 23 7/8, a record. The stock was up 1 5/8 on volume of 279,600 shares.

Cohen reiterated that there are "no plans to sell the company. No one has offered to purchase it. We have not been approached by Supermarkets General the New Jersey parent of Pathmark stores nor a European food chain. And we won't go private in a leveraged buyout because Charlotte says no." Charlotte Lehrman, the widow of co-founder Jacob Lehrman, owns half of Giant's voting stock. Cohen, whose father co-founded Giant 50 years ago next February, owns the other half.

Giant, the country's 40th-largest retailer, ranked fourth in profitability among supermarkets last year, according to Fortune magazine. Following a lean period, caused partly by cutthroat pricing wars with competitors, Giant has been very profitable for the past 3 1/2 years. Net earnings amounted to 2.42 percent of sales in the first quarter of its 1986 fiscal year. This compares with margins of half that size for most of the supermarket industry.

Much of the emphasis at yesterday's meeting was on growth. Giant plans to open 23 food/drug stores over the next three years. Two units were opened in Herndon and Hayfield, Va., in May and June. On Sept. 9, construction will begin on a new store in Glen Burnie, Md., and in October, building will start on stores in Charlottesville, Va., and Frederick, Md. Giant currently operates 132 supermarkets in the Washington metropolitan area.

The company reported some progress in negotiations with citizens of Potomac Falls, Md., over the size of a store Giant wants to establish there. Management has offered to reduce the store's size from the standard 55,330 square feet to 40,000 square feet.

Cohen said Giant had no plans to open more large gourmet stores. He told stockholders that "it took quite a while for the first gourmet store opened in 1983 to become profitable." When asked if Giant intended to establish more warehouse stores, he termed them "an experiment for us."

The company inaugurated production of its private-label soft drinks this week and plans to start making ice later in the year.