Preservatives In Dog Food

preservatives in dog food

Synthetic preservatives in dog food are chemicals added during the manufacturing process. They’re sprayed on the outside of food to retard spoilage, discoloration, or contamination by bacteria and other disease organisms. 

They’re a contrast to natural ways of preserving food that include freezing, fermentation, pickling, curing and canning. 

Natural Preservatives in Dog Food

First, here are 2 natural preservatives that some companies may use:


Antioxidants are used as preservatives for shelf stable foods to prevent oxidation of fats and degradation of water-soluble nutrients. Natural antioxidants are preferred as artificial antioxidants have limited toxicity studies and may be linked to cancer. Tocopherols are a family of compounds made up of different forms of vitamin E.

Alpha-tocopherols are the preferred form, and it’s the only one allowed in human vitamin E supplements. Alpha-tocopherols are found naturally in nuts and seeds, like almonds or sunflower seeds. But you’ll also see mixed tocopherols on food labels as a preservative. These are a combination of alpha, beta, delta and gamma-tocopherols. Mixed tocopherols are found in vegetable oils as well as grains, seeds and nuts. Tocopherols are used in vegetable fats and oils, dairy products, meat, eggs, cereals and nuts.

Synthetic tocopherols are usually shown as dl-alpha tocopherol on labels. This is made from petroleum products and should be avoided. It’s also less effective as a preservative than natural tocopherols.

Rosemary Oil

Rosemary oil is an oil soluble natural preservative used to preserve fats. 

But chemical preservatives in dog food are common. Here’s what you need to watch for.

Synthetic Preservatives In Dog Food

The following preservatives can lead to health issues in your dog.


Ascorbates are water-soluble antioxidants used to preserve carbs and proteins. You’ll see one listed as ascorbic acid. This is the chemical version of vitamin C. It’s used to prevent foods, especially fruits and meat, from browning when exposed to the air.

BHA (Butylated Hydroxyanisole): 

BHA has led to precancerous tissue in the stomach, retarded growth, behavioral effects and increased mortality in offspring. It’s also considered a hormone disruptor. BHA is used as an antioxidant and preservative in food, food packaging and animal feed … and that means dog food. 

BHT (Butylated Hydroxytoluene)

BHT is a potential hepatotoxin (meaning it’s toxic to the liver) and can lead to hepatic carcinoma (liver cancer). It’s also considered a hormone disruptor. BHT is regularly used to preserve fats, color, texture and oils. It’s also a synthetic antioxidant used in processed foods. 

Benzoic Acid, Sodium Benzoate 

These may be genotoxic. These are chemicals that can damage the genetic information within a cell and cause mutations … and they can lead to cancer. They can cause skin rashes and itchy, inflamed skin. They’re used as an antimicrobial food preservative.


This is another potential hepatotoxin that can damage the liver. It’s used in some pet foods to reduce the development of rancid fats.

Propyl Gallate

This is a potential endocrine disruptor and carcinogen. It’s a synthetic antioxidant used in foods including oils and fats. 

Propylene Glycol

This is a potential cause of allergies and immunotoxicity and has caused anemia in cats. It’s banned in cat food. It’s added to preserve moisture as well as dissolve colors and flavors. It’s also used in antifreeze and industrial products. 

TBHQ (Tert-butylhydroquinone)

The National Library of Medicine (NLM) has found TBHQ to cause liver enlargement, neurotoxic effects, convulsions and paralysis in laboratory animals. It’s used to extend shelf life and prevent fats from going rancid. 

Of course, the best way to avoid synthetic and artificial preservatives and chemicals in dog food is to feed your dog a fresh, whole food, raw meat diet. Then you’ll avoid the commercial foods that use chemicals to add shelf life to these over-processed foods.


Amadasi A, Mozzarelli A, Meda C, et al. Identification of xenoestrogens in food additives by an integrated in silico and in vitro approach. Chemical Research in Toxicology. 2009 Jan;22(1):52-63

Center for Science in the Public Interest. TBHQ (tert-butylhydroquinone). 2022 Feb 3. 

Environmental Working Group.

Jeong SH, Kim BY, Kang HG, et al. Effects of butylated hydroxyanisole on the development and functions of reproductive system in rats. Toxicology. 2005; 208(1):49-62.

Nair B. Final report on the safety assessment of Benzyl Alcohol, Benzoic Acid, and Sodium Benzoate. International Journal of Toxicology. 2001;20 Suppl 3:23-50.

Panel on Food Additives and Nutrient Sources added to Food (ANS); Scientific Opinion on the re-evaluation of BHT (E 321) as a food additive. EFSA (European Food Safety Authority) Journal. 2012; 10(3):2588.

Zagorski JW, Maser TP, Liby KT, et al. Nrf2-dependent and -independent effects of tert-butylhydroquinone, CDDO-Im, and H2O2 in human Jurkat T cells as determined by CRISPR/Cas9 gene editing. J Pharmacol Exp Ther.tr5 2017 May;361(2):259-267

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