By David Madden

PHILADELPHIA (CBS) – It’s that time of year again down the shore where cops go undercover to find underage drinkers and those who accommodate them.

‘Cops in Shops’ has been in place for 16 years now and New Jersey Attorney General Jeffrey Chiesa says it’s proven to be an effective tool for law enforcement.

“This isn’t just 19 and 20-year-olds that get the alcohol. It’s 14 and 15-year-olds. So it’s a health issue. It’s a community safety issue and it’s something that we’re going to treat very aggressively.”

Thirty shore police departments are taking part putting officers in liquor stores and nightclubs. The idea is not only to catch young people trying to palm themselves off as 21 but to prevent those over 21 from getting booze for those underage.

Last summer arrests were up by more than 50-percent.