Recently published studies regarding pet foods, over-the-counter products, and medications are revealing that some of these products have more ingredients than are actually listed on their labels.

The consequences of these incorrect product labels range from annoyed pet owners who are upset that they don't truly know what they're feeding their pets, to veterinarians conducting flawed dietary elimination trials due to unlisted antigens in products.

Study finds that mystery meat is on the menu for some pets

A recent study published in the journal Food Control revealed that a relatively high percentage of commercial foods for dogs and cats are mislabeled.

The study, conducted by researchers from Chapman University's Food Science Program, analyzed 52 products to determine whether the products' ingredient labels correctly identified the meats contained. They used DNA testing to test each product for goat, chicken, beef, lamb, turkey, goose, horse, and pork.

According to the study results, 31 of the 52 products featured correct labels, 20 were potentially mislabeled, and one contained an unidentified non-specific meat ingredient. Additionally:

• The 20 potentially mislabeled products consisted of 13 dog foods and seven cat foods.
• Of those 20 products, 16 contained meat species that were not included on the product label. Pork was the most common undeclared meat.
• In three of the 20 potentially mislabeled products, one or two meat species were substituted for other meat species.

Rosalee Hellberg, Ph.D., a co-author on the study, said food mislabeling is a concern especially in cases where certain foods are specially formulated for dogs and cats with food allergies.

Unexpected antigens found in some OTC products and medications

Foods aren't the only pet products with potentially incorrect labels that could affect animals with food allergies.

A study published in the September/October edition of the Journal of the American Animal Hospital Association tested several flavored over-the-counter (OTC) products and medications in search of antigens that could confound dietary elimination trials. 

The researchers tested three OTC products and four veterinary therapeutics for unlisted soy, beef, and pork ingredients. Three products contained ingredients that correctly matched their labels. Of the remaining four products that contained ingredients missing from their labels:

• One heartworm preventative chewable tablet tested positive for soy and beef.
• One heartworm preventative flavor tablet tested positive for pork.
• One arthritis supplement capsule tested positive for pork.
• One arthritis supplement chewable tablet tested positive for soy and pork.

Researchers reported that when they contacted manufacturers of the products, all manufacturers readily provided the protein components of the other ingredients in their products.

Based on their results, the study authors recommended that veterinarians:

• Contact manufacturers of oral therapeutics before prescribing them during a dietary elimination trial. 
• Contact manufacturers regarding "natural" and "artificial" flavors before feeding products containing those ingredients.
• Avoid feeding gelatin capsules during dietary elimination trials due to their potential for containing beef or pork proteins.