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Nutrition Nuggets is the newest offshoot of petMD's Dog Nutrition Center. Each week Dr. Coates will use her expertise and wisdom to blog about the intricacies of dog nutrition.

The Pros and Cons of Preservatives in Dog Foods

December 07, 2012 / (3) comments

Unless you are making your dog’s diet from scratch and serving it immediately, preserving dog food in some way is essential. Without preservation, food quickly spoils and can produce illness rather than the good health we are all looking to provide through optimal nutrition. There are many ways to preserve commercially prepared dog food, each of which has advantages as well as drawbacks. Read on to determine which is best for you and your dog.

Artificial Preservatives in Dog Food

Commonly used artificial preservatives in dry dog foods include ethoxyquin, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). They are very effective at preventing fats from becoming rancid (the primary problem we face in preserving dry dog food) and can greatly extend the product’s shelf life (a year is typical). On the other hand, some studies have linked the ingestion of large amounts of ethoxyquin to health problems. While there is certainly no "smoking gun" out there indicating most pets need to avoid the levels of artificial preservatives currently present in dry food, out of an abundance of caution, many owners understandably prefer to avoid feeding them to their dogs.

Natural Preservatives in Dog Food

Adding natural substances such as such as vitamin E (mixed tocopherols), vitamin C (ascorbic acid), and plant extracts (e.g., rosemary) to a dry dog food can also prevent fats from becoming rancid. Unfortunately, natural preservatives are effective for shorter periods of time than are artificial preservatives, which means naturally preserved foods tend to have a shorter shelf life. As long as you purchase bags well before the "best by" date printed on the label and don’t buy excessively large amounts of food at one time, this shouldn’t be a big concern, however.

To determine whether or not a dry dog food contains only natural preservatives, look at the ingredient list. Remember that descriptions like "all natural" on the front of the bag can mean almost anything. If you see ethoxyquin, BHT, and/or BHA in the ingredient list, the food is not naturally preserved.

Preserving Canned Dog Food

Feeding only canned food is another way to avoid artificial preservatives. The canning process is one of the most effective preservation methods available, so no artificial or natural preservatives need to be included in the food itself. Unopened canned food can last for years when stored in a cool, dry environment, although owners should still observe the “best by” dates that are printed on the label. Canned food is significantly more expensive than is dry (and generates more waste) but is another option for owners who want to get the artificial preservatives out of their dog’s diet.


Of course, what type of preservatives are used in a food is not the only (or even the most important) issue involved in how best to feed dogs. A combination of high quality ingredients that altogether provide balanced nutrition is what is nonnegotiable.

Dr. Jennifer Coates

Image: Homemade Airedale Chow by Lulu Hoeller / via Flickr

Comments  3

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  • Big Words
    12/07/2012 11:54am

    It is my opinion that if you can't pronounce it probably should not be fed to our critters. Or ourselves for that matter.

  • Big Words
    12/09/2012 04:24am

    Perhaps the fact that I have training in nutrition based chemistry is why I am not as worried about the terminology in foods as some pet owners would be. That would explain a lot in regards to why other posters seldom agree with me.

    Canned foods are "safe" because they have been processed at very high heat for long periods of time in comparison to other forms of food packaging, especially when the ingredients are meat based, (alkali).

    I agree with avoiding the terms that Dr Coates has mentioned above, such as the ethoxyquin and BHT, which DOES rule out fish caught at sea: http://www.woodhavenlabs.com/fishmeal.html so I don't see how avoiding a processing method can be a safe answer.

  • 12/09/2012 04:27am

    My husband has just reminded me that canned foods also contain BPA in the linings, and is suspected of causing the increase in thyroid issues in cats.