NEW CANAAN, Conn. — Services were held here last week for Brian Petronella, the longtime president of United Food and Commercial Workers Local 371, who died the preceding week at age 54, the Westport, Conn.-based union said. Petronella had been Local 371's president since 1999, playing a key role in negotiations between workers and supermarket employers, and acting as an advocate for food workers in Connecticut. Most recently, Local 371 negotiated a four-year contract for Stop & Shop workers, and helped bartenders at Foxwoods Casino join the UFCW. Petronella joined Local 371 of the Amalgamated Meat Cutters in 1972. He is a former vice president of UFCW International.