Using two explorer scouts, Fairfax County police arrested 29 store clerks last month on charges of selling beer to minors, police said yesterday.

Police said it was the first time the department has made a systematic, countywide check of retail establishments that sell beer and wines. Package sales of hard liquor are restricted to Virginia Alcoholic Beverage Control (ABC) stores.

"There was a universal feeling we should be trying to crack down,", Police Chief Carroll D. Buracker said. He said enforcement is part of his department's response to the recent community interest in tougher drunk driving and liquor sales laws.

The Virginia General Assembly, which is expected to consider a number of liquor proposals including one to raise the drinking age, convenes its 1983 session Wednesday.

Buracker said that although a substantial number of stores is complying with the law, the 29 arrests "clearly indicate a problem."

During the survey of 82 stores throughout the county, police used two teen-aged members of the police department-sponsored West Springfield Law Enforcement Explorer Post, accompanied by two plain- clothes officers.

The two explorers, both under 19--the lower legal limit for the sale of beer for off-premises consumption in Virginia--entered the targeted stores and attempted to buy a six-pack of beer. If they succeeded, an undercover policeman would arrest the sales clerk on the misdemeanor charge of selling alcoholic beverages to a minor.

If found guilty of the charge, each clerk could be fined up to $500 and sentenced to up to 12 months in jail.

Police also said the stores also could face action by the Virginia ABC Board, which issues licenses to sell alcoholic beverages.

At two People's Drug Stores where police made arrests, "the managers were so concerned about the violation that they dismissed the offending clerk on the spot," police said.

Police said they randomly selected outlets of most major retail convenience chains in the county, but targeted several outlets that had generated numerous complaints of sales to minors.

Nine of the 29 arrests were made at High's Dairy Stores; police visited 18 of those stores. The enforcement team visited 34 7-Eleven Stores, making arrests at five. Police said they also made arrests at six People's Drug Stores, four Drug Fair Stores, three Dart Drug Stores, and two independent pharmacies. They said no arrests were made at any of the individually owned "mom and pop" stores they checked.

Twenty-two of those arrested were adults and seven were juveniles, police said.

A similar spot-check operation will be conducted again within the next three months, officials said.