PHOENIX -- In less than a week, unionized workers at two grocery store chains may be walking a picket line instead of stocking shelves and cutting meat.

Fry's Food Stores has begun advertising for thousands of temporary workers in the event its estimated 13,000 hourly workers in Arizona strike.

Fry's recruitment ads offer a starting wage of $9.50 per hour.

Safeway spokeswoman Cathy Kloos said the chain is preparing to do the same.

The United Food and Commercial Workers Union Local 99 has threatened to call a strike if the companies and the union fail to reach a contract deal by 6 p.m. Friday.

Health care benefits are the main issue. The companies have traditionally paid for their employees' health insurance and now want them to shoulder more of the cost.