Giant Food Inc. fired eight of its store managers last week for allegedly falsifying vacation pay records, officials of the Landover-based company confirmed yesterday.

The supermarket chain is considering possible criminal action against the former employes for a series of apparently unrelated incidents that cost the company "less than $50,000," said spokesman Barry Scher.

Scher said an internal audit had turned up "irregularities in vacation pay" claimed over the past three years by eight of the firm's 129 store managers.

While refusing to provide details of the irregularities, Scher and other Giant executives said the incidents involved more than just taking an unauthorized day off and getting paid for it.

Managers of Giant stores have wide-ranging responsibilities for operating their stores and work on what amounts to an "honor system" in keeping track of vacation time they have coming, said sources familiar with the company's operations.

Industry sources said the store managers may have been able not only to take off more vacation time than they were due, but also to collect vacation pay while they were drawing their regular salaries.

Because employe theft of goods and services can have a devastating effect on supermarket profits that average little more than 1 percent of sales, Giant and others in the business traditionally take a tough stand on even minor infractions. "I've had to fight with them when they wanted to fire somebody for eating a doughnut," said one union official who represents Giant employes.

Store managers are not members of Local 400 of the United Food and Commercial Workers Union, which represents other Giant workers.

"A severe violation of policy is a terminating offense," replied another Giant spokesman, when asked why the managers were fired.