A very disturbing article was published in the Australian Veterinary Practitioner.

A cat fed exclusively a “no-name” commercial pet meat from a supermarket developed signs of thiamine deficiency. The food contained harmful levels of sulphur dioxide preservatives. The cat experienced general tremors, downward flexion of the neck and an inability to stand. It responded to an injection of thiamine (vitamin B1) and supportive care within 24hours.

Sulphur dioxide & sulphite preservatives are commonly added to pet meat to increase the shelf-life, reduce signs of spoilage and maintain the red colour. Their identity numbers are 220, 221, 222, 223, 224, 225 & 228. The concern is that no regulations exist for the addition of these preservatives to pet meat despite over 20 years of awareness of their dangers in Australia. Sulphur dioxides continue to be found in commercial pet meats at harmful concentrations. Surveys of pet meat in 1997 & 2005 found varying levels of sulphur dioxide and sulphite preventatives plus a proportion failed to list their presence on the packaging.

Thiamine (vitaminB1) is an important for energy metabolism and the manufacture of neural transmitters in the brain. Deficiency causes swelling and cell death within specific areas of the brain. There are three phases of clinical signs:

  1. inappetance, vomiting and lethargy
  2. neurological signs including impaired vision, pupil changes most often dilation, manic behaviour and downward flexion of the neck
  3. death

Sudden death has been noted due to heart failure.

The simplest preventions of this syndrome is to avoid feeding pet meat high in sulphides and do feed a commercial complete cat or dog food. Clients who insist on feeding a “natural” diet should be advised to purchase low-fat meat sold for human consumption for which appropriate legislation precludes the addition of preservatives that cause thiamine deficiency. The diet should also be supplemented with natural sources of thiamine such as pork, organ meats such as liver, heart, brain & kidney, yeast, oatmeal & whole wheat.

This case highlights the lack of regulation of fresh meat products sold for pet consumption. Although the pet food industry is self-regulated under the Pet Food Industry Association of Australia (PFIAA) Code of Practice, which mandates adherence to Australian Standards (AS5812:2011), including requirements for minimum thiamine concentrations in pet food, pet food producers do not operate under the microscope.


Probable dietary-induced thiamine deficiency in a cat fed pet meat containing sulphur dioxide preservative. Fawcett A, Yao Y, Miller R Aust Vet Pract 2014; 44 (1): 554-559

Probable dietary-induced thiamine deficiency was diagnosed in a cat fed pet meat containing high levels of sulphur dioxide preservative. The cat presented after an acute onset of neurologic signs including muscle fasciculations, ventroflexion of the neck and inability to stand. Exposure to environmental toxins was unlikely. The cat was fed exclusively a commercial, kangaroo meat pet food purchased from a supermarket. The food was tested and demonstrated high concentrations of sulphur dioxide, a known cause of thiamine deficiency in cats. The cat improved clinically with thiamine supplementation. Testing of the food confirmed the presence of sulphur dioxide preservatives. Despite previous reports of thiamine deficiency in cats fed similar diets, sulphur dioxide preservatives continue to be found in some commercial pet foods. Regulation of sulphur dioxide concentrations in pet food may reduce the incidence of clinical and subclinical cases of thiamine deficiency.

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