Beef and poultry products sold to US consumers contain relatively high levels of antibiotic-resistant bacteria, according to a preliminary survey conducted by the Food and Drug Administration (FDA). Scientists believe that the spread of such drug-resistant bacteria could pose a major health threat both with the US and across the globe by breeding resistance to a wide range of helpful drugs.

The study, which analysed samples of meat from several supermarkets in the Washington DC area, found that strains of the Enterococcus family of bacteria in the meat showed “fairly substantial amounts of resistance to a number of drugs.” These types of bacteria are usually harmless in humans, but for scientists they act as a useful indicator of drug resistance. Twenty-nine drugs were tested in all.

While 67% of the chicken samples and 66% of the beef samples gathered showed up the Enterococci bacteria, it was only found in 34% of the turkey samples. The researchers found however that the bacterial strains in the poultry products tended to be “much more resistant to the antibiotics,” than those in red meat.

Presenting the report to the annual meeting for the American Society for Microbiology on Tuesday, FDA microbiologist Dr David Wagner stressed that while the results needed further investigation, because the tests only used a relatively small sample, they could form a “background” to help the FDA decide “whether or not […] to take an intervention strategy” with reference to the amount or types of drugs used in meat production in the US.

“There is a movement afoot to try and develop a national program to try and control antimicrobial resistance and I think this could very well be put in as part of that,” he added.

Antibiotics are routinely added to livestock feed because they boost animals’ growth rates.