Both processed/manufactured pet food and raw 'pet meat' products can contain preservatives. There may be no legal requirement to label pet food products as containing preservatives.
There are safety issues relating to sulphur dioxide and sodium and potassium sulphite preservatives - these can cause thiamine deficiency, which can be fatal.
Products specifically marketed for pets such as commercial fresh 'pet meat'; 'pet mince' or processed/manufactured 'pet food rolls' may contain sulphite or potassium sulphite preservatives (sulphur dioxide 220, sodium sulphite 221, sodium bisulphite 222, sodium metabisulphite 223, potassium metabisulphite 224, potassium sulphite 225 and potassium bisulphite 228) that liberate sulphur dioxide.
Thiamine (Vitamin B1) deficiency can occur when dogs and cats are fed on a diet containing sulphite preservatives. Thiamine deficiency causes severe neurological symptoms and can be fatal. For decades, sulphite preservative induced thiamine deficiency has been frequently recognised by the Australian Veterinary profession. (please note that thiamine deficiency can also occur when sulphur dioxide containing foods are fed in conjunction with foods not containing sulphur dioxide. This is because the sulphur dioxide in one food can destroy any thiamine present in the other food being fed at the same time).
An Australian Standard for Pet food is currently being developed (due to be released early 2011) - this standard addresses this issue by including a mandatory requirement that any product containing sulphur dioxide, sulphite or potassium sulphites must contain sufficient thiamine according to AAFCO guidelines, for the entire shelf-life of the product. This will help to prevent thiamine deficiency in relation to manufactured pet food.
However, RSPCA Australia still has concerns about 'raw pet meat' products containing sulphite preservatives which we have raised and we await developments on this issue. The pet meat industry must ensure they take steps to safeguard pets from thiamine deficiency by including a mandatory requirement that any 'pet meat' product containing sulphur dioxide, sulphite or potassium sulphites must contain sufficient thiamine according to AAFCO guidelines, for the entire shelf-life of the product. This will be the requirement for any 'manufactured pet food' that complies with the Ausralian Standard and should be the requirement for any 'raw pet meat' products aswell.
Sodium benzoate (E211) is another preservative used in a range of pet food products and products for human consumption. Cats appear to have a significantly lower tolerance against benzoic acid compared to rats and mice. At certain doses this preservative may be toxic to cats.
To avoid any potential problems associated with preservatives the following precautions may be taken by pet owners:
- Choose high quality premium commercial foods that include a full list of ingredients on the packaging. You may also wish to contact the company directly to enquire about the ingredients including the addition of any preservatives. It may also be worthwhile asking if the product has been tested by the Association of American Feed Control Officials (AAFCO).
- Feed raw meat/meat products that are labelled for human consumption only - you may wish to obtain meat products from your local butcher, where appropriate legislation usually affords protection against the use of preservatives in human-grade meat products.
- Feed a varied diet.
If you are concerned about the lack of regulation of the pet food industry, including the lack of a requirement to provide accurate labelling information relating to preservatives, we suggest you contact your local MP to express these concerns. Please see the article How can I lobby government to improve animal welfare? for further information.
Articles of interest
- Thiamine deficiency due to sulphur dioxide preservative in ‘pet meat’– a case of deja vu Australian Veterinary Journal Volume 83, No 7, July 2005
- Bedford PG, Clarke EG (1972). "Experimental benzoic acid poisoning in the cat:. Vet rec (90):53-58
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