Resistant bacteria ‘no concern at all’ if food properly cooked

Researchers are continuing to study the threat of antibiotic-resistant pathogens and how they could compromise food safety.

A recent study in Alberta surveyed retail meat for resistance.

Mueen Aslam, a research scientist for Agriculture Canada, conducted the study of chicken, turkey, beef and pork samples, which isolated three types of commensal bacteria: E. coli, enterococci and salmonella.

These are forms of bacteria that are normally present in animals and humans and don’t cause infection.

Other strains of bacteria, such as E. coli O157:H7, are familiar to producers and consumers for their potential health risk.

However, for this survey, Aslam was concerned if the bacteria was resistant to antibiotics used to treat infections in humans and animals.

“The importance was only if these bacteria carry resistant genes in them they can spread to the other bacteria also,” he said.

Resistant genes can be transmitted to other species, and with many antibiotics used in human medicine as well as animal production, there has been a move in recent years to guard against the spread of resistance through prudent use of antibiotics in animals, with some calls to increase restrictions.

For the study, 500 samples were taken from Alberta grocery stores, with Aslam finding the greatest occurrence of resistant bacteria in poultry.

For example, enterococcus was found in 94 percent of poultry samples and, while no resistance was found to many “clinically important drugs,” resistance to some were common, including tetracyclines, macrolides and streptogramin.

“This study underscores the importance of (enterococcus faecalis) as a reservoir of resistance and virulence genes and their potential transfer to humans through consumption of contaminated undercooked meat,” reads the report.

Aslam said the results, which mirror those from surveys conducted in other provinces, didn’t surprise researchers.

“We did not have any critical or any new findings,” he said.

“(It) was important that we generate the data in Alberta and now the policy maker will have a better idea of how far spread this antimicrobial resistance is in bacteria.”

The survey results will contribute to other data collected by the Canadian Integrated Program for Antimicrobial Resistance, which monitors resistance levels as one way to gauge human exposure.

A previous study that examined antimicrobial resistance among feedlot cattle in southern Alberta found that more than 90 percent of antibiotics given to cattle are Category 3 drugs, including tetracyclines, and aren’t used to treat more serious illnesses in humans.

In that study, resistance to Category 3 drugs was most common, while resistance to category 1 and 2 drugs was low.

Among E. coli samples, less than 30 percent were resistant to multiple antibiotics, although the study supports continued long-term funding for surveillance.

“If we do not properly cook our meat, then these bacteria can get into humans,” said Aslam.

“Generally when we cook our meat properly, they’re no longer there. They’re done. That way, no concern at all.”

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