Dog food 101: What are preservatives?

While scanning the label of your dog food, you might see some preservatives. Canned food is preserved by the air-tight container, but dried foods must contain a preservative to prevent spoilage. Artificial (also known as synthetic) preservatives can produce an apporoximate twelve-month shelf life while natural preservatives cut that amount down to six months.  Read on to learn about some common preservatives found in dog food.

BHA (Butylated hydroxyanisole)

BHA is a synthetic or artificial preservative commonly found in dry dog food. It is very similar to BHT and is a waxy solid used to prevent oxidation of dry food. Some sources have claimed that BHA is a potential cause of cancer in dogs.

BHT (Butylated hydroxytoluene)

A common artificial preservative much like BHA, this fat-soluble compound is used as a food additive to prevent the degredation or spoilage of dog food. BHA is also used in cosmetics, pharmaceuticals, jet fuels, rubber, petroleum products, electrical transformer oil, and embalming fluid. Like BHA, some state that BHT can cause cancer.

Ethoxyquin

This is another commly used synthetic preservative. Ethoxyquin causes the most concern among dog owners. Like BHA and BHT, some experts have claimed a potential link to pet cancer. Several studies, including one by the Department of Pathology at Nagoya City University Medical School in Japan has found Ethoxyquin to promote kidney and bladder cancer and stomach tumors. Ethoxyquin has also been blamed as a cause of disease, skin porblems, and infertility. This dog food preservative is currently regulated by the FDA as a pesticide.

Propyl gallate

Propyl gallate is a less frequently used artificial preservative that has also been linked to cancer. It is also used in skin antiseptics, astringents, cosmetics, hair products, adhesives, and lubricants.

Propylene glycol

An artificial preservative that is a less toxic version of antifreeze and is used to de-ice aircraft. Propylene glycol is used as an ingredient in paint balls, a working fluid in hydraulic presses, poison for ground beetles, pipe tobacco addittive to prevent drying, and in deodorant sticks.  Propylene glycol is not allowed in cat food as it has been shown to cause anemia. However, it is still permitted in dog foods.

Vitamin C (ascorbate) and Vitamin E (mixed tocopherols)

These are both natural preservatives. Dog foods containing Vitamin C or E will have a shelf life of six months, which is about half that of a food containing artificial preservatives.

Oils of rosemary, clove, or other spices

Spice oils are less commonly used but can also serve as a natural preservative, meaning that the food's shelf life will be about six months.

It is important to note that a food may be advertised as having "no added artificial preservatives", they may still contain low levels synthetic preservatives that previously existed in the meat or vitamins purchased from suppliers.