Feeding your dog a raw meat-based diet is seen by some owners as a healthier and more natural alternative to commercially available pet food.
But researchers warned in a new study that many of the raw meat products for dogs they looked at contained high levels of bacteria that could put both people and animals at risk of infection.
The researchers, who were based in Sweden, analyzed 60 frozen packs of raw dog food made by 10 manufacturers in Sweden, Norway, Finland, Germany and the UK for bacteria that could pose a health risk.
Thirty-one packs contained levels of bacteria that exceeded the threshold set by the European Union, including salmonella, which was found in four packs, and campylobacter , a common cause of food poisoning. Clostridium perfringens, a marker of contamination from feces and poor hygiene standards, was found in 18 samples.
Levels varied widely among manufacturers and, in some cases, among products from the same manufacturer.
The results of the study, which was published Monday in the BMJ journal Vet Record, showed that it was "highly important" to handle raw dog food carefully and maintain good hygiene.
The researchers said that bacteria in the juices from raw meat dog food could splash and spread to other foods and surfaces, and dogs could transfer potentially harmful bacteria by "kissing" faces immediately after eating.
The study recommended that raw food not be fed to dogs in homes where infants, the elderly or others with compromised immune systems lived.
"This research offers further compelling evidence to support vets' concerns about the potential animal and public health risks associated with feeding pets a raw meat-based diet," said Daniella Dos Santos, junior vice president at the British Veterinary Association.
"We would advise any owner wanting to try a raw meat-based diet for their pet to first consult a veterinary surgeon."
If you're feeding your dog raw meat, the researchers said, keep it frozen until it's used, and thaw it at a maximum of 10 degrees Celsius (50 degrees Fahrenheit). The thawed raw meat should be kept separate from human food and handled with separate kitchen equipment.
The raw-meat based dog food analyzed in the study contained uncooked meat, edible bones and organs from beef, chicken, lamb, turkey, pig, duck, reindeer or salmon. The food didn't undergo any form of heat treatment to eliminate or reduce microbial content.