Grocery workers should be ready to strike if their union can’t reach agreement with management in 72 hours, UFCW Local 770 told its members Thursday night.

All six Southern California locals of the United Food and Commercial Workers International Union put the management of Vons, Ralphs and Albertsons on 72-hour notice Thursday, saying they won’t renew their contract, which expired in March.

The two sides have been negotiating for “16 straight days,” UFCW Local 770 said in a statement, over wages and health care coverage.

The three supermarket companies – Safeway, which owns Vons; Kroger Co., which owns Ralphs and Food 4 Less; and Supervalu, which owns Albertsons – have been negotiating as a group, as have the six UFCW locals, which represent approximately 62,000 workers in those supermarkets across Southern California.

“Employers are still offering no wages for most workers and refuse to adequately fund our health plan,” UFCW Local 770 said in the Thursday night notice to members.

“This does not mean workers will walk out in 72 hours,” it said. “Negotiations continue but you should be prepared to strike if necessary.”

It said workers should call their union representative for further information.