Mark Kastel, co-director of the nonprofit institute, said he and other researchers visited at least a dozen Wal-Mart stores in four states throughout the Midwest to see how organic items were selling.

But they found problems, he said, such as dairy coolers stocked with regular yogurt -- by brands that also make organic varieties -- near signs that say 'organic.' Similar, misleading labels were found on produce and throughout aisles, he said.

Kastel said the company has not provided adequate training to managers to make sure the food meets government guidelines.

"Obviously Wal-Mart wants to put the premium on price so they haven't put that management oversight in place," Kastel said.

Wal-Mart's response, as reported in The Washington Post:

In an e-mail, Wal-Mart spokeswoman Karen A. Burk wrote "it's hard to take their claims seriously" and said one of the group's founders, Mark Kastel, had worked for a Wal-Mart rival. Kastel was a consultant for Organic Valley, a national farming cooperative that competes with several of Wal-Mart's suppliers.

To claim that Organic Valley -- a co-op of family farms -- is somehow a rival of the largest retailer on earth is not just bullshit but truly baffling.