Samples of beef taken from cows raised conventionally were found to contain twice the amount of dangerous superbugs than those taken from sustainably produced beef, according to recent research from Consumer Reports.

The tests revealed that 18% of conventional ground beef harbored superbugs resistant to at least three classes of antibiotics suitable for humans, while just 9% of sustainably produced beef were similarly affected.

The full report acts as a response to 2014 data from the Centers for Disease Control and Prevention (CDC), which estimated that 48 million Americans are affected by food poisoning every year, with 128,000 of that number hospitalized and 3,000 dying as a result. Beef was found to be one of the top sources of foodborne illness, potentially due to the American preference for consuming the meat rare.

Consumer Reports carried out testing on both conventionally and sustainably produced beef from 26 cities through the US, focusing on common bacteria including: clostridium perfringens; E. Coli; enterococcus; salmonella; and staphylococcus aureus.

Although bacteria was present on all beef samples, the results demonstrated that sustainably produced beef from cows reared without antibiotics or on an organic or grass-based diet, was less likely to contain S. aureus and E. coli – two strains of bacteria that can pose serious health risks.

Recommendations included in the report called for the US Food and Drug Administration (FDA) and the US Department of Agriculture (USDA) to ban the use of antibiotics when rearing healthy cattle, impose stricter inspections at processing plants and ban the sale of beef containing bacteria resistant to antibiotics.

The report, entitled ‘How Safe is Your Beef’ will feature in the Consumer Reports October issue.