After a yearlong investigation dubbed “Operation Swill,” 29 New Jersey bars and restaurants have been accused of filling premium brand liquor bottles with cheap booze in order to increase profits. Over 100 investigators descended on the establishments yesterday morning, including a dozen TGI Friday’s in Freehold Township, Hazley and Marlboro, and confiscated both liquor and records. The operation was conducted by the state Division of Alcoholic Beverage Control detectives and the state Division of Criminal Justice in response to numerous complaints from customers and confidential informants, as well as booze samples taken covertly by detectives using new technology. “The customer paid for the premium brand, but was instead, unbeknownst to the customer, poured the non-premium brand,” said authorities. TGI Fridays claims to be “working closely with the franchisee and owner of the cited locations to review and investigate these serious allegations,” the company said in a statement, “We have one of the most extensive bar and beverage programs in the industry, which sets a very high standard in the quality and service of our beverages.” Last year, TGI Friday’s reported annual sales of over $2.6 billion.