A tentative agreement was reached late Saturday night between the unions representing grocery workers and their employers that if ratified will avert a grocery strike during Thanksgiving week.

Details of the agreement will not be released until after the grocery store workers’ vote on the offer has been concluded, according to Tom Geiger, a spokesman for UFCW Local 21. There was no immediate indication when unions members would vote on the contract.

That local, along with UFCW 81 and Teamsters 38, represent workers with Allied Employers, including Safeway, QFC, Fred Meyer and Albertsons.

A strike would not have affected family owned or independently owned grocery stores.

A new round of negotiations began on Thursday; talks have been under way since March.

Earlier, grocery-store workers in King, Snohomish and Kitsap counties attended meetings in Seattle, SeaTac, Lynnwood, Bremerton and Bellevue, who on Nov. 10 rejected with 94 percent of the vote the employers’ offer and authorized a strike.

Negotiations have been under way since mid-March; differences had remained over pay, health benefit and pensions.

Those cuts were repeated by workers as they voted to reject the offer, according to an earlier union press release. Grocery-store workers have seen their hours cut in recent years to an average of 28 hours per week, according to the union.

The UFCW 21 is the state’s largest private sector union with more than 36,000 workers in grocery store, retail, health care and other industry jobs.