LOS ANGELES (AP) — Thousands of southern and central California grocery workers have started voting on whether to authorize their union to call a strike against several major supermarket chains.

About 47,000 workers at more than 500 Ralphs, Albertsons, Vons and Pavilions stores are eligible to vote and results are expected to be released on Sunday.

The possible strike would involve grocery clerks, meat cutters, pharmacists and pharmacy technicians represented by seven locals of the United Food and Commercial Workers. Negotiations ended without agreement before the latest three-year contracts expired this month.

A strike and lockout in 2003 and 2004 for nearly 70,000 Southern California grocery workers lasted more than four months.