WASHINGTON — Antibiotics don’t affect the levels of antimicrobial resistance in ground beef, according to a new study conducted by U.S. Department of Agriculture researchers that appeared in the Journal of Food Protection.

Antimicrobial use in U.S. cattle production has “minimal to no impact on (antimicrobial resistance) AMR in the resident bacteria," the study said.

The World Health Organization and other public health groups have called for limits on the use of antibiotics in livestock and poultry, arguing that widespread use of these drugs for growth promotion and disease prevention in healthy animals contributes to the emergence of drug-resistant pathogens, which can be transmitted to humans through meat, according to the center.

That concern has resulted in growing consumer demand for meat raised without the use of medically important antibiotics. The biggest impact has been seen in the poultry industry, as several major chain restaurants and poultry producers have committed to removing medically important antibiotics from the supply chain. Advocates for antibiotic-free meat are now pushing the beef and pork industries to make similar changes.

But the authors of the study say there has been little peer-reviewed research that supports claims that meat products raised without antibiotics harbor lower levels of antibiotic-resistant bacteria, and most of it involves poultry. They say their findings suggest those claims may not be warranted for ground beef.