"Underage drinking occurs when you're not paying attention," he said.
Christy's participated in a seminar for liquor retailers about preventing underage drinking.
"After the seminar, when you see something that doesn't feel right [you investigate]," he said.
Edward J. Boyle, the owner of BuyRite Liquors in Cambridge, said he was also eager to participate in the program.
"All of the retailers in Cambridge are participating because we felt strongly that the minors that came in to purchase alcohol kept coming in and were never dissuaded," Boyle said.
"This is the first time the law has any teeth in it," he said.
The Century Council has also emphasized the deterrent value of the program, saying that it has been successful in turning teenagers away from liquor, stores through posters and advertising.
Boyle and Effi both said they were not afraid of losing business by participating in the program.
"Minors usually buy a case of beer and I make a dollar. I want them for customers when they're 21 but not before that," Boyle said.
"[The program] is going to work well. I know you at Harvard have a major problem with [underage drinking] down there," Boyle, whose daughter recently graduated from the College, said.