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Nutrition Team Blog

Pet food preservatives to avoid

Published: Wednesday, January 28, 2015

Naturally preserved 

We’ve had a few queries lately about additives in pet food, so we thought we’d explain about the type of chemical preservatives to watch out for.

Why add additives?

Preservatives are essential for dry food, otherwise the fat oxidises – in other words it goes rancid. Moist food doesn’t need a preservative because sealing the can or the pouch stops air getting in. As a bag of dry food remains open, air can find its way in and react with the contents.


Natural preservatives

We’re pleased to label our food as ‘natural’, and that includes the preservatives we use. These are Vitamin E (a tocopheroland Rosemary Oil - we’ve been using them since 1996. 

Chemical preservatives

Manufacturers use chemical preservatives instead of natural preservatives as they are cheaper. There’s a large list of chemical preservatives out there, not all of which are obvious to spot straight away. Here are some of the more common ones you might find in an ingredients list (and not just in dog food!).The FDA (Food and Drug Association) in America considers a small consumption of artificial preservatives as safe – but when your pet has them in every meal, every day, that’s a cause for concern and we’d want to avoid them!   

Also known as
E number
Also found in
Official line

Butylated Hydroxytoluene



  • Food packaging
  • Cosmetics
  • Rubber products
  • Petroleum products

The World Health Organization has named both BHT and BHA as suspicious cancer-causing compounds. 

Butylated Hydroxyanisole



  • Packaging materials
  • Food containing fats and oils

As above. In addition, the State of California has now identified BHA as a possible carcinogen (an agent directly involved in causing cancer).




  • Pesticides
  • Hardening agent for making rubber

Not permitted for use in Australian dog foods and not approved within the European Union, Ethoxyquin in dry pet food has been found to:

  • promote kidney carcinogenesis 
  • significantly increase the incidence of stomach tumours 
  • enhanced bladder carcinogenesis 
  • significantly increased the number of colon tumours 

Propylene glycol



  • Antifreeze
  • E-cigarettes

Although it’s allowed in dog food, PG was banned in cat food in 1996 by the FDA.

This is because the more propylene glycol in a cat's food, the more ‘Heinz Bodies’ are produced, which are damaging to red blood cells.

Tertiary Butylhydroquinone



  • Stabilize certain explosive compound
  • Varnishes
  • Lacquers
  • Resins

A study by the International Programme on Chemical Safety discovered that TBHQ produced pre-cancerous stomach tumors in laboratory animals and can also cause damage to a cell’s DNA. Prolonged exposure to TBHQ can also lead to other types of cancer

Propyl gallate



  • Human and Pet Food
  • Adhesives
  • Hair products
  • Lubricants
  • Gum and sweets

Gallates aren’t permitted in infant or children’s food in the UK as they have been linked to the blood disorder methemoglobin. High doses of gallates in humans can cause gastric or skin irritation.

Study by Nagoya City University Medical School, Japan

International Programme on Chemical Safety 

Gharavi N, El-Kadi A (2005), “Tert-Butylhydroquinone is a novel aryl hydrocarbon receptor ligand”, Drug Metab Dispos 33 (3): 365–72

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