You may want to rethink your dog’s raw food diet: According to a recent study published online in the International Journal of Food Microbiology, raw dog food commercially available in Europe contains drug-resistant Enterococcus bacteria. Scientists from the University of Porto and Instituto Universitário de Ciências da Saúde (IUCS) in Portugal tested 55 types of dry, wet, and raw dog food for Enterococcus, which can cause everything from urinary tract infections to endocarditis in humans. They found it in more than half the samples—including every single raw one.
Dr. Ana R. Freitas, the study’s primary author, published a research letter in the CDC’s Emerging Infectious Disease journal that discusses the results from the raw samples in detail. To put it nicely, they’re not “good”:
All samples carried enterococci resistant to erythromycin, streptomycin, chloramphenicol, and tetracycline; 93% resistant to ampicillin, ciprofloxacin, and quinupristin/dalfopristin; 79% resistant to gentamicin; and 50% resistant to linezolid.
Linezolid is a last-resort antibiotic, and fully half the bacteria strains from these raw dog food samples are resistant to it.
Dr. Freitas and her team also found that some of the dog food bacteria are closely related to Enterococcus strains found in pigs, chickens, wastewater, and even hospitalized human patients across Europe—so we know they have the ability to infect multiple species. Dr. Freitas concludes the letter with this: “Our data suggest that raw dog food could be a sentinel of emerging antimicrobial resistance traits … adding a new concern to the global health burden of antimicrobial resistance.”
The degree to which you should be freaking out right now depends on where you live and what you feed your dog. This study only tested dog food brands available in Portugal (and Europe), but unfortunately, the authors didn’t disclose any names. They just said that they tested two raw dog food brands, one produced in Europe and one produced in the United Kingdom. If your brand comes from either of those places, you should toss it and transition your dog to kibble or regular wet food.
Even if your preferred brand is produced elsewhere, though, this study should give you pause about the whole “raw dog food” thing. The findings are pretty terrifying, to be sure—but given what we already know about raw food diets for pets, they’re also kind of unsurprising. The CDC doesn’t recommend them mainly because raw meat contains bacteria that can make both pets and humans sick. A 2019 literature review in the Journal of Small Animal Practice weighed the proposed benefits of raw diets with the risks and concluded that “the advice against raw feeding issued by various professional bodies appears justified,” especially for anyone who’s extra vulnerable to bacterial infection. In fact, one piece of evidence cited to support this conclusion is the “increased frequency and number of antimicrobial drug‐resistant bacteria in raw foods.”
The bottom line is that raw foods are way riskier for pets and humans than anything that’s been heat-treated. Listeria and salmonella are one thing, but drug-resistant Enterococcus is serious, life-threatening stuff. With antibiotic and antimicrobial resistance already on the rise, you can’t be too careful there.