A city-wide sting operation cracking down on alcohol sales to minors found several Harvard Square stores repeatedly violating state law, according to city licensing officials.

Cardullo's Brattle Street gourmet shop sold alcohol to three different undercover, underaged police constables over three days, police records say.

Louie's Superette, a Surrey Street establishment popular with students from Dunster and Mather Houses, sold to underage constables twice without asking them for identification, according to records provided by city licensing officials.

The Broadway Market, near the Yard and the Union dorms, was also cited by the city for selling beer twice to underage customers.

Cheng-San Chen, the owner of Louie's said last night that he doesn't think his workers would sell alcohol to minors, though he was not aware ofthe specific purchases.

Joseph P. Devine, manager of the Broadway,said, "I know we got caught twice." He said hebelieves such sting operations are a fair andappropriate tactic by police and licensingofficials. Cardullo's employees refused tocomment.

The License Commission will vote at a January12 hearing on disciplinary action against thesestores and 12 others that sold beer at least onceto underage constables.

Richard V. Scali, executive officer of theLicense Commission, said he is suggesting punitiveliquor license suspensions of one or two days forthe one-time violators and up to a week for thethree time violator. He said other city officialsmay favor educating, or certifying, store workers.

In the first round of the sting, 15 of thecity's 39 package stores sold liquor to a 20-yearold constable during the first half of December.Of the 15 violators, nine sold to another underageofficer in the second round of the investigation,which targeted first-round violators. Only one ofthe nine second-round violators sold to a thirdconstable, said Scali.

"A lot of them are not doing it intentionally,"he said. "They just aren't aware that someone wholooks like they're 22 might not be 22."

License Commisioner Alex P. Rodriguez said theviolations were fewer than he expected. The stingoperation will soon include bars, with the goal ofreaching "every pouring establishment that has aliquor license in Cambridge," he said