SAN FRANCISCO (CBS SF) — A consumer watchdog group is sounding an alarm over the food recall policies of the nation’s largest supermarket chains.

In a 32-page report released Wednesday, the non-profit Public Interest Research Group (PIRG) said that 22 of the 26 chains it surveyed earned an “F” when it comes to developing and implementing policies designed to keep the public safe from dangerously contaminated food.

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Food Recall Response report card (CALPIRG)

The stores failed to “adequately inform the public about recall notification efforts, how to sign up for direct notifications or where to find in-store postings,” according to PIRG.

“Supermarkets should be our best recall notification system, but instead, we found that shoppers must go on a nearly impossible scavenger hunt to learn if they’ve purchased contaminated food,” said Laura Deehan, a health advocate with the CALPIRG Education Fund.

“Stores already use modern technology to track customers, place products, and target us with ads. There’s no reason why they can’t also keep us healthy,” Deehan said in a news release.

The nation’s food recalls for meat, poultry and egg products are issued by the U.S. Department of Agriculture’s Food Safety and Inspection Service.

Recalls for other food, including pet and animal feed, are issued by the U.S. Food and Drug Administration.

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Those agencies, as well as the Centers for Disease Control and Prevention, which tracks food-borne illnesses, rely heavily on media outlets to alert the public during a recall.

Supermarkets play a key role by removing tainted products from shelves and, ideally, alerting customers about the recalls.

Too often, however, the country’s major chains make it difficult for people to access information about recalls in a timely and comprehensive way, according to PIRG’s report, “Food Recall Failure: Will your supermarket warn you about hazardous food?”

Of the 26 supermarket chains surveyed, only four earned a passing grade: Harris Teeter, Kroger, Smith’s Food and Drug, and Target.

Whole Foods Market, Safeway and Trader Joe’s are among the stores that earned an “F” in PIRG’s report.

Representatives from those chains didn’t immediately respond to calls or emails asking for their reactions to the report.

In order to improve the country’s food recall system, PIRG says the federal government should require stores to make notification policies available on their websites, and post signs about major recalls at cash registers and store shelves for at least two weeks for perishable food and for at least one month for frozen food.

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Stores should also be required to create systems that can directly alert customers about recalled products within 48 hours of a recall announcement, according to PIRG.