When 69-year-old Mildred Claypool wants to go grocery shopping she has to beg a neighbor to drive her.

Living on food stamps and a fixed income, and walking with the aid of a thick, black cane. Claypool can't afford the $3.30 round trip taxi fare plus 10 cent-a-bag parcel charge it costs to get from her Northwest home to the nearest large grocery store five blocks away.

"You go to the corner Mom and Pop stores and they charge twice as much - a half gallon of milk cost $1.09 and you could get it at Safeway for 79 cents," she told a group of about 50 consumers and specialists at a Food Market Hearing in the District Building yesterday. "What we need is a bus that would take senior citizens to the stores."

Claypool was one of 31 witnesses, including city officials, consumer activists and representatives of chain and independent food stores, who testified on the problems surrounding the disappearance of food stores in the District.

Sponsored by the Food Market Committee of the Mayor's Commission on Food. Nutrition and Health, the hearing was an attempt to formulate a list of recommended solutions to deal with the problem of supermarkets gradually leaving the inner city, according to commission chairperson Alice Bruce.

Four major chains had 91 stores in operation in the District in 1968, and today two major chains operate a total of 41 stores, according to testimony by the U.S. Department of Agriculture's Food Distribution Research Lab.

"Grand Union, Acme and Food Fair have left the city altogether," noted Janice Rodgers of the Community Nutrition Institute. "The Anacostia area, with a population approaching 200,000, is presently served by five supermar- kets, although it could support approximately 15 to 20."

"Our clients have to travel 10 or more blocks to a large chain grocery store," testified Thelma Washington, consumer adviser for the Center City Community Corporation. "Adding salt to the wound of having to travel this distance, they must also make purchases in stores that are basically understocked, lack competent management and have seemingly unsanitary conditions in some areas."

Joseph Danzansky, chairman of the board for Giant Food, Inc. which operates seven of its 115 metropolitan area retail stores in the District, cited crime, the difficulty in acquiring large land parcels, and high operating costs as the three major problems confronting inner city food retailers.

As an example of how to attract to chain stores back to the city. Danzansky pointed to his company's O Street Market in Northwest which is scheduled to open in 1979 as the inner city's first new chain supermarket in ll years.

The store will be jointly leased by the Giant, the D.C. Development Corporation and the Shaw Community Citizens Pact, acting together as partners.

The area's other major retail food chain, Safeway which has 34 district outlets, currently has four major projects under way in the District - three new stores replacing older stores and a major remodeling and store expansion at 14th Street and Kentucky Avenue SE - said Safeway spokesman. Therman Stantom.

The biggest obstacle facing independent grocers is the difficulty of obtaining financing, according to George Shelton, owner of Shelton Market Basket at 12th Street and Pennsylvania Avenue Se.