In 2018, a team of veterinary scientists noticed an odd trend among a sample of Swiss dogs and cats. In a group of 64 animals, over half carried spectrum beta-lactamases (EBSL)-producing germs. These germs are a problem for pets and people alike. EBSL are enzymes that can make certain antibiotics not work, and in turn, they underlie the signature move of antimicrobial resistant bacteria.
Public health experts have warned that antimicrobial resistance is one of the most pressing threats to human and animal health — so the fact that pets contained bacteria that make antibiotics lose their effectiveness was a concern. But the University of Zurich team behind the research had a good guess as to what was causing this to happen: BARF, or the “biologically appropriate raw food.” That’s a diet of raw muscle and organ meats, as well as meaty bones.
To test their hypothesis, the team purchased 51 samples of raw pet food formulated for dogs, either online or from pet stores near their laboratory, and tested the meats for enterobacteria. While some strains of enterobacteria are harmless, the family also includes pathogens like Escherichia coli and Salmonella, some of which are antibiotic-resistant.
The team revealed Wednesday in the journal Royal Society Open Science that the raw meat sampled here turned out not to be something you want to give to man’s best friend. Nearly 73 percent of the samples contained levels of enterobacteria that exceed the amount the European Union says is safe for pets to eat, while antibiotic-resistant strains of bacteria were found in 63 percent of the samples. Furthermore, Salmonella was found in 3.9 percent of the samples, and one sample contained E. coli.