Dogs are more likely to pass on illness-causing bacteria to their owners if fed raw dog food, according to new findings.
Raw dog food is marketed by companies as a more 'natural' pet food, but the research reports that bacteria from this type of diet can cause diseases in humans.
Two studies by Bristol University scientists showed dogs are more likely to excrete E. coli. Some strains of this bacteria commonly cause urinary tract infections (UTIs) and sepsis, a life-threatening reaction to infections.
"E. coli is a widespread bacterium found in the intestines of all humans and animals," explained lead author Professor Matthew Avison.
"However it's a common cause of many diseases including urinary tract infection and can cause serious illness including sepsis if it spreads to other parts of the body."
Prof Avison cited growing evidence that not feeding dogs raw meat helps reduce the spread of antibiotic-resistant bacteria, Wales Online reported.
"We should do everything we can to reduce the circulation of critically important antibiotic-resistant E. coli and other bacteria. Our research adds to the increasing evidence that not feeding raw meat to dogs may help in that objective."
He warned owners to be cautious, adding: "People should take extra precautions when handling it - and be especially careful to clean up afterwards."
Co-author Prof Kristen Reyher said: "We know humans and animals share bacteria with one another - so what we find in your pet may well also be in you. Pet owners should be encouraged to practice good hygiene and not feeding raw food to your dog can be part of this.
"We can all do our part to decrease antibiotic resistance and its terrible effects on both human and animal health."
Two analyses, involving 223 puppies and 600 adult dogs, identified links between eating raw meat and excreting resistant E. coli. Using data from different groups demonstrated the phenomenon - regardless of age or length of time spent on the diet.
It was a strong risk factor for those living in the countryside. The issue was much more complicated for city-dwellers due to a variety of lifestyles and exposures. Owners completed questionnaires about their dogs diets and environment - and provided faecal samples from them.
Prof Avison added: "Antibiotic-resistant bacteria are everywhere, but some antibiotics are considered critically important for use in humans. We have shown dogs fed raw meat are more likely to carry bacteria resistant to these important medicines. This doesn't mean that the animal, or the owner, will become sick."
Last year Portuguese scientists branded uncooked dog food an "international public health risk."
They examined 25 major brands from supermarkets and pet shops and found multidrug-resistant bacteria identical to those found in patients. Superbugs are expected to kill 10 million people annually by 2050 if no action is taken.
The World Health Organisation (WHO) has described it as "one of the greatest public health threats facing humanity."
The latest British findings were published in One Health and the Journal of Antimicrobial Chemotherapy.
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