LITTLE ROCK, Ark. – The U.S. Department of Agriculture said Tuesday that Tyson Foods Inc. routinely gave chickens sold as “raised without antibiotics” an antibiotic that can be used in humans on top of another it gave.

According to the Associated Press, undersecretary for food safety Richard Raymond said the meat producer had used gentamicin on poultry. The antibiotic is used in the United States to treat a variety of infections in humans.

Tyson on Monday announced it was withdrawing its “raised without antibiotics” label after a lawsuit from competing companies accusing Tyson of misleading advertising. Tyson does use ionophores, which are not used in humans and not believe to raise health concerns.

Amanda Eamich, a USDA spokeswoman, told the news service the agency also sent a letter Monday night to Tyson, warning that it could not consider its no-antibiotics label as "truthful and accurate." The agency has given the company a deadline of June 18 to stop using the labels.

“The FSIS letter rescinding approval of our chicken Raised Without Antibiotics label claim was received last night, after we formally notified FSIS of our plans to withdraw the claim voluntarily,” said Tyson spokesman Gary Mickelson. “While we agree with the agency that a public process is needed to sort out the many nuances of label claims describing on-farm practices, we respectfully disagree with the limited timeframe we've been given to change our label and with any statements suggesting our products are anything less than safe and wholesome.”

Mickelson said that Tyson was questioned about its pre-hatch practices after receiving qualified approval for the claims. The company explained it process that is says is standard in the industry: egg vaccination with small amounts of antibiotic.

“We believe this practice to be consistent with other "raising" claims,” Mickelson said. “In fact, this is the standard for organic chicken labeling and other marketing claims for ‘raising’ practices. According to The Organic Foods Production Act of 1990 ‘Poultry or edible poultry products must be from poultry that has been under continuous organic management beginning no later than the second day of life.’ ”