LOS ANGELES (CBSLA.com/AP) — One out of three grocery workers in California is receiving some type of public assistance while one in five rations the food he or she helps sell, according to a study released Monday.

KNX 1070’s Claudia Peschiutta reports University of California researchers – commissioned by labor union United Food and Commercial Workers – interviewed 925 people who work for supermarket chains, smaller ethnic markets or in the grocery sections of big box retailers such as Wal-Mart and Target.

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In what’s being billed as one of the largest surveys ever done of the state’s grocery industry workforce of nearly 384,000, the “Shelved: Report on CA’s Food Retail Workers” study found that the median wage at unionized stores fell from $19.38 in 2000 to $15.17 an hour in 2012, with workers at non-union shops earning less than $10 an hour.

The report’s authors criticized the Safeway and Albertsons chains in particular for using profits to enrich investors instead of reward employees and praised Costco for paying its workers comparatively well, the Associated Press reports.

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“One thing that stood out for me is it’s been a long term trend in declining wages in the food sector but increased wages in the rest of the economy,” said UC Davis community and regional development professor Chris Benner, one of the study’s authors.

A private equity firm that already owns Albertsons, Cerberus Capital Management, is in the process of buying Safeway for $9.4 billion. The deal should benefit both workers and customers, Safeway spokeswoman Teena Massingill said.

The United Food and Commercial Workers Western States Council, which commissioned the study, is the regional coordinating body of 11 UFCW local unions representing over 200,000 workers in California, Arizona, Nevada and Utah, according to the group’s website.

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