THE NEXT TIME farmers, food dealers or grocers in Virginia do any poor-mouthing to explain the high costs of their goods, they had better remember exactly who pushed hardest to keep a 4 percent tax on all the groceries people buy in the state. For at least six years now, legislators from both parties have been trying to get rid of this most regressive and cruel part of the state sales tax -- but each time, lobbyists for those who grow and sell food have strongly opposed any move to give consumers even the slightest staple-break at the store.

The way these groups would have it, any other kind of tax or increase is a threat to mankind, something to bemoan in the loudest political terms. Yet to these same groups, any talk of exempting food from the sales tax somehow doesn't spell relief. Even when sponsors of the legislation try, as they are in this session, to phase out the taxing of food over many years, the farmers, food dealers and grocers object.

Perhaps it is too much to ask of some of these organizations that they consider which groups of people are most hurt by each different tax proposal. It is true that raising the tax on gasoline to cover transportation projects will cause strains on motorists. But surely the hardships of a 4 percent tax on groceries must serve to explain the vigorous support for a food exemption as voiced in Richmond this week by representatives of the elderly, consumers, blue-collar workers and civil rights organizations.

Some 25 states (including Maryland) and the District of Columbia have recognized that the poor and the old are hardest hit by rising food prices and therefore do not tax food. But in Richmond, one hears from a Farm Bureau lobbyist that "it's a uniformly fair tax that serves as a vehicle for all individuals to pay their fair share." Since when does 4 percent of the price of the same basic market basket amount to the same percentage of everybody's income?

Some of these lobbists do say they would support some income-tax credit for people below a certain income level or some other form of rebate. This way, the government would do all the paper work and stores wouldn't have to adjust their operations to handle taxable and non-taxable items they sell under the same roof. Merchants elsewhere seem to handle this bookkeeping well enough; but if this is the most the General Assembly might do this year, it would be a small step in the right direction. Still, the preferable approach is to stop the practice altogether, on the principle that the tax on food is fundamentally wrong in the first place.