PETS are being poisoned by dangerous levels of preservatives in commercial pet food that can leave dogs and cats with brain damage, veterinarians have warned.

Some pet food suppliers treat products with high levels of sulfur dioxide to preserve the meat and to disguise signs of putrification.

But vets are calling for tough rules to limit the amount of chemicals used because it is proven to cause thiamine deficiency and lead to neurological problems.

Dr Anne Fawcett, companion animal veterinarian at the University of Sydney’s Faculty of Vet Science, treated a thiamine deficient cat fed exclusively on supermarket bought kangaroo meat packaged for pets.

The food was tested and found to have concentrations of sulphur dioxide almost double that allowed for human consumption. Sulphur dioxide is a known cause of thiamine deficiency in humans and animals.

“In this day and age, with the knowledge that pet food manufacturers have, this is an entirely preventable condition,” Dr Fawcett said.

“A one-off meal won’t hurt but over time these levels of sulphur dioxide cause vitamin b deficiency which causes brain damage.”

Dr Anne Fawcett

“Sulphite preservatives are added to some pet meats, sometimes at very high levels, to mask the signs of putrefaction, giving it a longer shelf life. But long-term consumption endangers the wellbeing of our pets,” Dr Fawcett said.

“A one-off meal won’t hurt but over time these levels of sulphur dioxide cause vitamin b deficiency which causes brain damage.”

Her findings were published in the Australian Veterinary Practitioner.

The pet food industry is self-regulated, with the Pet Food Industry Association of Australia Code of Practice requiring manufacturers adhere to Australian Standards. But fresh pet meat producers do not operate under the same guidelines.

“Sulphite preservatives continue to be found in some pet foods at harmful concentrations. We need to ensure that the levels of these preservatives in all pet foods are regulated,” Dr Fawcett said.

“Until there is a change in the way pet meat is regulated, I would only feed my pets human grade meat.”

The cat she examined, called Puss Puss, showed no signs of harm until she could no longer walk, said her owner Alana Dixon, 28, of Balmain.

“She just couldn’t walk, I didn’t see any symptoms until she was flat on the floor helpless, it was really scary,” Ms Dixon said.

“Until there is a change in the way pet meat is regulated, I would only feed my pets human grade meat.”

Dr Anne Fawcett

“I thought I was doing the right thing and feeding her nice ‘roo meat and it nearly killed her. My dog and cat are like children to me, so it was horrific.

“I am angry beyond imagination to find I had done this to my cat,” she said.

RSPCA head vet Magdoline Awad reiterated calls for regulation of the pet food industry as did Dr Richard Malek from the Centre for Veterinary Education University of Sydney.

“There needs to be an organisation that controls what goes in pet food because you can do whatever you want,” Dr Malek said.

“No one controls what goes in pet food, most add preservatives and some add hideous amounts and a lot claim they don’t add it when they do.”

The Department of Agriculture, Fisheries and Forestry established the Pet Food Controls Working Group in 2009 to manage the safety of imported and domestically produced pet meat and food but there has been no action on regulation.