Keith Williams, a U.S. Department of Agriculture spokesman, said investigators have found no cases of illness related to the recalled meat.
The beef recall came after inspectors said they found "clear violations" of USDA regulations at a California slaughterhouse that has been accused of mistreating cows.
"We do not know how much of this product is out there at this time. We do not feel this product presents a health risk of any significance," said Dick Raymond, the undersecretary of agriculture for food safety. "But the product was produced in noncompliance with our regulations, so therefore we do have to take this action."
Federal officials called the recall by Westland/Hallmark Meat Packing Company the largest beef recall in U.S. history.