SOUTH PORTLAND, Maine (AP)   A food workers union that represents employees at a Maine distribution center says it has rejected a contract proposal and will go on strike.

The 250 workers are members of United Food and Commercial Workers Local 1445 who work at the Hannaford Distribution Center in South Portland. The union says the current three-year contract expired at midnight Saturday.

The union says in a statement that members voted “overwhelmingly” to authorize a strike, and that there was “disappointing and unacceptable movement from Hannaford in key important economic areas.” Spokesman Jim Carvalho says the union will plan the strike if the company doesn’t come to the table.

A Hannaford spokesman didn’t immediately return a call seeking comment from The Associated Press.

The union represents 15,000 workers in Maine, New Hampshire and Massachusetts.