Take local grocery stores and chains eager for a tax write-off for food they wouldn't be able to sell. Add local charities eager to find an easier way to feed large numbers of hungry people.

Put the two together and you have a new food clearinghouse, the Capital Area Community Food Bank, which will open here today in a warehouse on 25th Place NE in the District.

The food bank will collect over-stocked and slightly damaged products in large quantities from wholesalers and retailers. The food will then be redistributed to charitable agencies that provide meals or emergency food packages to the needy, the ill, the elderly and infants.

"We know the food bank cannot solve the ills of the hungry in D.C.," said its director, Richard Stack. "We're not going to take the place of federal feeding programs . . . . You might say we're more like a Band-aid" to the community.

The food bank has been able to salvage 10 tons of food so far -- canned fruits and vegetables, frozen beans, baby food, condiments and salad dressing -- most of which would have been thrown out by stores.

The food was contributed primarliy by the local Safeway and Giant stores, a similar food bank in Baltimore and Second Harvest, a Phoenix, based clearinghouse that distributes food to 21 food banks nationwide.

Second Harvest started the first food bank in Phoenix 14 years ago, but the phenomena has really taken off over the past four years, since the Tax Reform Act of 1976 gave the food industry an added incentive to donate food rather than destroy it.

Under the law, corporations can deduct not only the value of the donated food but half of what its retail mark-up would have been -- usually about 20 percent of the cost, according to the industry.

Food bank officials figure that a pound of food, on average, is worth 70 cents. Thus if a store gave the food bank 70,000 pounds of food -- as Giant gave the Baltimore bank for the first two months of this year -- it would be able to deduct $53,900 -- $49,000 for the food and $4,900 of the markup. Before the law was changed, only the $49,000 could be deducted.

Spokesmen for the chains declined to say how much the stores have donated to the food banks.

Safeway and Giant spokesmen said that it is easier to donate food to the food banks than to smaller charities because they are equipped to pick up and store large amounts of food on short notice. Previously, the stores had to call cozens of smaller charities, who had to pick up the food in station wagons.

The bank here is being funded by the United Planning Organization, the Interfaith Conference of Metropolitan Washington and private foundations. In addition, Mayor Marion Barry has pledged $30,000 to the effort.

The food bank wil not distribute the food to individuals, according to Stack, but only to registered, tax-exempt agencies. So far, 32 local agencies have registered with the bank.

Most corporations make the banks agree not to distribute to individuals, said John Von Hengel, director of Second Harvest, lest the free food hurt their regular market. "They would prefer to see the 100 cans of soup in a soup kitchen pot than on the shelves of someone who would otherwise buy the product."

Stack said that by October he hopes to be distributing 61 tons of food a month -- the same level as the Baltimore food bank. The food bank in Phoenix distributed 2 million pounds of food last year to 286 charities for 27,000 people.

Local agencies have high expectations for the bank. "It will save us a lot of money on staples," said Lynn Bossidy, food coordinator of SOME (So Others Might Eat), a soup kitchen at 71 O St. NW that serves more than 250 homeless people daily. Bossidy said that money can now be put into the group's dental and counseling clinics.

"We have great hopes [that the food bank] is going to keep our food closet stocked," said Elanor Kennedy, director of Alexandria's United Community Ministries. Kennedy said that while the bank would not save her agency money, it would enable it to distribute more and better emergency food packages.

Even before it officially opened, the bank was able to help some of the District's needy, Stack said. It recently provided five tons of food to more than 400 residents of Southeast Washington whose welfare checks and food stamp certifications were stolen before they were delivered.