Raw Pet Food Found Contaminated with Multi-Drug Resistant Pathogenic Bacteria. Again.

A study out of Zurich that looked at raw dog and cat food raises concerns for animal and public health. The study aimed to evaluate commercially available raw meat pet diets about microbiological quality and the occurrence of antimicrobial-resistant Enterobacteriaceae.

What the scientists found was alarming.

They found that the majority of commercially produced raw foods on the European market contained high levels of harmful bacteria—including strains that could transmit diseases to pets and their owners alike.

While the study was small, most of the raw meat diets sampled did not meet the microbiological standards for Enterobacteriaceae set out by EU regulations for animal by-products intended for pet food. And of the samples tested, antimicrobial-resistant bacteria were found in over half the pet food samples, the majority thereof were resistant to third-generation cephalosporin.


“It is really worrying that we found EBSL-producing bacteria in over 60 percent of samples,” said first author Magdalena Nuesch-Inderbinen, a researcher at the University of Zurich, referring to an enzyme that renders some antibiotics ineffective.

“They include several types of E. coli which can cause infections in humans and animals. We, therefore, advise all dog and cat owners who want to feed their pets a BARF diet to handle the food carefully and maintain strict hygiene standards. Pet owners should be aware of the risk that their pet may be carrying multidrug-resistant bacteria and can spread them.”


Pets that consume contaminated pet treats and raw food diets can be colonized with organisms without exhibiting clinical signs, making them a possible hidden source of contamination in the household.
Consumers who feed raw pet food need to be aware of the risks and handle raw pet food appropriately, much in the same way that raw meat and poultry are handled for human consumption. But there is one major difference: If a pet eats contaminated food, there is a possibility – however remote – that pets can shed bacteria and transmit that bacteria to humans. And consumers should weigh the risks of having young children without a fully developed immunity come into contact with uncooked pet food or with a pet that might be shedding harmful bacteria from being fed contaminated pet food.


To be clear, no one can say with any certainty what portion of human illnesses are the result of contact with infected pets and contaminated pet food products. The risk that the authors discuss is theoretical because there is no substantive data to apply to their risk assessment. However, despite the dearth of data, it does not mean they can’t infer that there exists a probability. 

We need to consider that there is no mechanism for tracking or reporting illnesses in animals because there is no animal equivalent to the Centers for Disease Control. The United States Food and Drug Administration (FDA) encourages veterinarians to report confirmed cases of salmonellosis to the Centers for Disease Control, but most do not because testing is expensive, and if testing is done, it’s only when a pet’s symptoms are severe or prolonged. And many veterinarians simply are unaware that there is a mechanism for reporting adverse food and drug events to the FDA. 


The raw food issue is never a pleasant topic to revisit because it is fraught with so many variables and no absolutes. But when considering the problem and the risks they might pose to us, we need to ask ourselves these questions: If you have an infant, would you allow her to be exposed to a pet that might be shedding a multidrug-resistant bacteria? Another consideration is the risk of listeria infection from raw meat which can cause stillbirths, miscarriages, and disease in newborns. Personally, if I were pregnant, my pets would have to survive without raw pet food for nine months.


Some pet food safety advocates would have you believe that studies like this one are part of some grand conspiracy to disenfranchise raw pet food manufacturers; that the study’s authors are secretly paid by the kibble manufacturers. That somehow, studies like these are a part of a secret plot designed to overthrow raw pet food manufacturers orchestrated by the FDA.

I do believe there is truth to the assertion that state and federal regulators focus their attention and resources on products that have a high probability of contamination with pathogenic bacteria. But not for the reason that the conspiracy theorists would have you believe.  I believe that the agency’s focus on raw agriculture products is because, by their very nature, they are more likely than cooked or sterile products to be contaminated. Because the FDA is woefully underfunded the agency allocates its resources – according to risk – as the most effective means of protecting public health. Therefore it only seems logical that raw pet food would be the focus of regulatory oversight.

NOTE: The findings, “Raw meat-based diets for companion animals: a potential source of transmission of pathogenic and antimicrobial-resistant Enterobacteriaceae,” were published in the Royal Society Open Science journal on October 16, 2019.

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Mollie Morrissette

Mollie Morrissette, the author of Poisoned Pets, is an animal food safety expert and consumer advisor. Help support her work by making a donation today.

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