Stop & Shop and its unionized workers are heading toward a strike. United Food and Commercial Workers 1459 says it served notice it will terminate its contract with the supermarket chain as of Friday at noon, as have two other UFCW locals in Rhode Island and Connectictut.

In a update posted on the UFCW site Thursday afternoon, President Scott Macey said the union was willing to negotiate with the supermarket through Friday for "a fair and reasonable offer." However, the union can call a job action at any point and strike without notice, he wrote.

UFCW 1459 covers workers in Berkshire County and Western Mass. Employees at the store in North Adams have said they're prepared to strike and that they've been told by loyal customers that they won't cross at picket line. Stop & Shop also operates two stores in Pittsfield.

Stop & Shop took advertisements in local newspapers for temporary help last month in anticipation of a breakdown in negotiations; talks between the chain and its union have been rocky and a federal mediator was called in to help with the talks.

On its Web site, the grocer stated that "negotiations are continuing and this does not necessarily mean there will be a work stoppage; however the locals would be free to initiate a work stoppage after the 24 hour period ends. If a work stoppage does occur, Stop & Shop may use temporary replacement workers to support our stores."

Any work stoppage would affect more than 300 workers in Berkshire County.

Update at 8:46 p.m.: The five union locals say they're scheduling votes for Sunday on a new offer from Stop & Shop, per federal mediators. According to postings on the UFCW Web site, talks are closer on health and pensions, but the locals feel there should be significant movement on wages and new hires. Stop &  Shop has consistently stated its workers are well paid compared to similar nonunion workplaces.

Update at 9:27 a.m. , March 7: The five union locals say they reached a tentative agreement on Saturday night. The union membership will vote this afternoon; Berkshire County union members will be presented the contract and will vote at the Holyoke Holiday Inn beginning at 3 p.m.

Update, 9:35 a.m., March 8: UCFW has voted to accept the contract offered by Stop & Shop. Some 400 employees in Berkshire County and Western Mass. attended a presentation Sunday on the offer, which passed 307-23. UCFW 1459 President Scott Macey said the contract protected many benefits and contained other improvements. In a posting on the Web site, Macey said the union got about 92 percent of what it wanted.

"Today was a very good day. We were able to present a very good package," he said. "Tremendous improvements in health and welfare and pension plan staying the same, and a few other improvements, I couldn't be happier with the outcome today."

Four other UCFW locals also approved the contract, averting a strike.