Although raw meat-based diets for pets have become increasingly popular, the meat may be contaminated with bacteria and parasites, a new study from the Netherlands shows.
Raw meals include dried treats such as pig ears, home-prepared meals and commercially-prepared meals with meats, meaty bones, organs, vegetables, eggs, grains, yeast, milk, and yogurt.
“The pathogens can be transmitted…to owners by direct contact with pets (sleeping with pets, licking the face, stroking the fur) or by cross-contamination of foods and utensils in the kitchen,” study coauthor Dr. Paul Overgaauw of Utrecht University told Reuters Health by email.
More than 200 commercial raw meat-based pet food products are available in the Netherlands. Dr. Overgaauw and colleagues analyzed the 35 frozen products most popular among pet owners across the country.
They looked for two strains of E. coli (one that’s associated with renal failure in humans, and one that’s considered antibiotic-resistant) as well as Listeria, Salmonella, and several parasites.
They found the first strain of E. coli in eight products, antibiotic-resistant E. coli in 28 products, one strain of Listeria in 19 products, additional strains of Listeria in 15 products, and Salmonella in seven products. Parasites were found in 10 products. Only five products weren’t contaminated.
In contrast, dry, semi-moist and canned pet foods rarely contain pathogens, the study authors wrote online January 11 in Veterinary Record.
“We have known for many years already that there are risks associated with raw meat diets for pets,” said Dr. Overgaauw.
“In nutritional terms, these diets are often deficient in several nutrients and may therefore lead to serious health problems,” he and his colleagues point out in their report.
“The most concerning aspect, from our public health point of view, is not only the high prevalence of potential pathogens that we found, but also that we found multi-drug resistant bacteria,” Dr. Overgaauw said.
“Sometimes owners almost become religious about these diets and don’t think there are any downsides,” said Dr. Oskar Nilsson of the National Veterinary Institute of Sweden in Uppsala. Nilsson, who wasn’t involved with this study, has studied the problem of E. coli in raw pet foods in Sweden.
“Simply put, all meat has bacteria in it if it is raw, and it doesn’t die if you freeze it,” he told Reuters Health by phone. “Some people think about frozen meat as sterile, but think about this as if you were feeding yourself. You cook it.”
The study wasn’t designed to find out whether and to what extent bacteria and parasites from these products actually get transmitted from pets to humans, and whether humans get sick as a result.
Nilsson also noted that because only a small number of products were tested, the numbers and percentages may not be generally applicable.
“You shouldn’t take them as absolute figures, but it proves the case,” he said. “Now we want to know more.”
Food safety technologies could help reduce the risk of bacteria in the products, said Dr. Jeff Bender of the University of Minnesota in Minneapolis, who studies food safety and antimicrobial resistance.
“The prevalence of E. coli was higher than I would expect, especially considering the potential for serious injuries in children,” Dr. Bender, who wasn’t involved in this study, told Reuters Health by email. “We should encourage the pet food industry to consider pasteurization for those using these diets.”
Warnings and handling instructions on packaging could help pet owners be aware of the possible bacteria and parasites in the products and know the proper hygiene for preparing meals in the kitchen to avoid cross-contamination, Dr. Overgaauw said.