What Preservative Is Bad in Dog Food?

Dog food needs a preservative to stay fresh. Without it, you'd have to buy your pooch's food fresh every day. Pet food manufacturers have several preservatives to choose from, some posing significant risks for your pup. Learn which preservatives to avoid when choosing a food for your canine companion.

One of the most dangerous preservatives in dog food is ethoxyquin. This harsh chemical is used not only to preserve fats in dog food, but also as a pesticide and a chemical in rubber. It has been banned for use in human food, but is still allowed to be used as a preservative in dog food. Be careful when choosing a food for your pup, as ethoxyquin only has to be listed if the manufacturer adds it directly. If this toxic preservative is added to an ingredient before it reaches the manufacturing plant, the dog food company doesn't have to list it -- so they usually don't. If you have any concerns, call the manufacturing company directly and ask them if they guarantee that their foods are free of ethoxyquin.

Butylated hydroxyanisole is a waxy chemical antioxidant used to preserve oils and fats in food. Many countries have banned the use of this chemical, but it is still legal in both human and pet food in the United States. As far back as 1980, both government and private studies of BHA have shown that even small amounts of BHA could be toxic. Although BHA is an effective preservative, the risks it poses to your canine companion are considerable.

Butylated hydroxytoluene is another antioxidant used to preserve fats and oils in foods. It is also used in cosmetics, fuels and embalming fluid. In laboratory studies, BHT has been linked urinary and thyroid cancer in rats. While BHT is still legal to use as a preservative in pet food, the risks are again too high when so many foods use safer preservatives.

Although not as common as ethoxyquin, BHA or BHT, other unsafe preservatives being used in dog food include tertiary butylhydroquinone and propylene glycol, although both have been proven to be dangerous to both people and their canine companions. In fact, propylene glycol is the main ingredient in antifreeze, which is extremely toxic to dogs.

Healthy preservatives in dog food are also made from antioxidants, but natural ones like vitamin E or C. Usually on the dog food label, vitamin E preservatives are listed as mixed tocopherols and vitamin C preservatives are listed as ascorbates or ascorbic acid. Other good natural preservatives include rosemary, sage and clove extracts. Higher-quality foods will almost always use one of these healthier preservatives.