Failed Study Confirms Long-Held Suspicions About Pet Food

Analysis by Dr. Karen Shaw Becker

mislabeled pet food ingredients

Story at-a-glance -

  • Researchers at North Carolina State University set out to study how much wild prey urban domesticated cats eat in addition to the food their owners offer
  • The study was unsuccessful because the research team discovered commercial cat food ingredients are highly variable, even those of the same brand and flavor
  • Pet food is also commonly mislabeled, according to recent studies — containing ingredients not on the label and/or not containing ingredients listed on the label
  • If you’re fed up with Big Pet Food, there’s no time like the present to begin providing your furry family member with a safe, nutritionally balanced, species-specific fresh diet

According to a recently published research article in the journal PeerJ,1 a team of scientists at North Carolina State University ran into an interesting, but unsurprising snafu that caused their study to fail when they attempted to determine how much wildlife urban pet cats eat in addition to the food their humans offer them.

According to the research team, at the end of the study they were still ignorant about why some cats kill more wildlife than others, and in addition, they found they were also ignorant about the shifting dynamics of Big Pet Food.

Ingredients Vary in Same Brand, Same Flavor Cat Foods

Some urban and suburban cat parents allow their furry family members unfettered access to the outdoors (why I don't recommend this). There are also kitties roaming loose on farms, ranches, and "out in the country" where free ranging is the lifestyle. It's assumed most of these cats hunt and eat wild prey from time to time in addition to the commercial pet food their guardians provide.

The NC State researchers set out to discover how much wild prey cats eat along with canned and kibble cat food by studying isotopes from things kitties might eat, including different brands and flavors of commercial cat diets. This is accomplished by collecting samples of the cats' fur, nails, or blood and analyzing its carbon and nitrogen isotopes. According to an NC State press release on the study:

"All organic materials contain isotopes of elements that get locked into body tissues, following the basic principle that you are what you eat. For example, the ratios of nitrogen isotopes present in carnivores are dependably distinct from those of plant eaters. Similarly, researchers can distinguish the types of plants that an animal eats by measuring the ratio of carbon isotopes."2

However, as a writer for the online publication CNET observed:

"… getting the answer was more difficult than expected thanks to something many cat owners have long suspected: Cat food manufacturers don't use the same type and amount of ingredients in every bag, even when food is the same brand and flavor(emphasis mine) …".3

The research team assumed the cats in their study would have an identical isotopic match to the food they consumed, and that any differences would point to the occasional wild prey snack. However, what they discovered was that isotopes in cat foods vary widely, even among the same brands and flavors.

"We really thought this was going to be an ideal application of the isotope methodology," said Roland Kays, a co-author of the study and scientist at NC State and the NC Museum of Natural Sciences. "Usually these studies are complicated by the variety of food a wild animal eats, but here we had the exact pet food people were giving their cats."4

The researchers also noted that 1) the cheapest commercial cat foods had higher carbon values, indicating more corn product in those formulas, and 2) cat foods sampled from the U.K. had lower carbon values (indicating less corn product).

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'Mystery Ingredients' in Pet Food Are Nothing New

The problem of "mystery ingredients" in pet food isn't new. One example: a 2015 study conducted at Chapman University in Orange, California raised serious concerns for every pet parent who depends on accurate ingredient listings on pet food labels.5 For the study, over 50 dog and cat diets were examined for evidence of "food fraud." According to Dr. Rosalee Hellberg, co-author of the study:

"Although regulations exist for pet foods, increase in international trade and globalization of the food supply have amplified the potential for food fraud to occur.

With the recent discovery of horsemeat in ground meat products sold for human consumption in several European countries, finding horsemeat in U.S. consumer food and pet food products is a concern, which is one of the reasons we wanted to do this study."6

The Chapman study tested 52 commercial dog and cat foods to determine what meat species were present, and any instances of mislabeling. For each product, DNA was extracted and tested for 8 types of meat: beef, goat, lamb, chicken, goose, turkey, pork, and horse.

Of the 52 Products Tested, 20 Were Mislabeled

A majority of the pet food tested by the researchers contained chicken, followed by pork, beef, turkey, and lamb, in that order. A few of the formulas contained goose; none contained horsemeat. Of the 52 products tested, 20 were "potentially" mislabeled, and one contained a non-specific meat ingredient that could not be verified.

Of the 20 mislabeled products, 13 were dog food and 7 were cat food. Of the 20, 16 contained meat species that were not listed on the product label, with pork being the most common unlisted ingredient. In three cases, one or two meat species were substituted for other meat species.

The Chapman researchers concluded that while pet foods are regulated by both federal and state entities, it's clear that mislabeling is occurring, though how it's happening, and whether or not it's intentional is unclear.

What to Do If You're Concerned About Misleading Pet Food Labels

In a 2012 study, 48% of tested dog food was mislabeled. In the Chapman University study, 38% of tested pet foods were mislabeled. That's a truly disturbing amount of mislabeled pet food, and even more frustrating is that neither study revealed the names or manufacturers of the mislabeled products.

If you're concerned about the ingredients in your pet's food — perhaps you have a dog or cat with allergies or who requires a novel diet to treat food sensitivities or bowel disease — you can try contacting the pet food manufacturer to ask how, and how often, they verify the authenticity of their ingredients. A few questions to ask:

Do you apply hazard analysis and critical control point (HACCP) procedures to avoid product adulteration and contamination?

Do you require your ingredient suppliers to verify the source, type and species content of grains and meals, meats and other raw materials used to make your products?

Do you check the quality of new suppliers by carefully examining their products, demand third party purity testing and test them yourself, as necessary?

Do you keep records of the receipt and use of each ingredient in your products?

What measures are in place in your production facility to prevent ingredient confusion and cross-contamination? What other foods are manufactured in the facility that makes your pet food?

Do you participate in third party transparency testing (such as Check Your Pet Food) and can you email me the results?

What to Do If You've Lost Trust in Ultra-Processed Pet Food

Thanks to mislabeled products, low-grade ingredients, too-frequent recalls, and an exploding population of pets with chronic digestive issues, allergies and degenerative disease, it's no wonder so many pet parents are exploring homemade diets, fresh food diets made by smaller, transparent pet food producers, raw diets and other alternatives to the dead, rendered, dubious, ultra-processed feed-grade "fast food".

My advice? Search this website for more information on choosing the best diet for your pet. There are dozens of videos and articles here that can help you become more knowledgeable about pet nutrition so that you can make the best diet choices for your own dog or cat. You can also learn what real transparency in pet diets looks like by ordering the Truth About Pet Food 2020 List.

If you want to help change the deceptive practices occurring in the pet food industry, I recommend becoming a member of the Association for Truth in Pet Food, which is the only organization out there committed to holding the regulatory agencies and AAFCO accountable. You can also check this list for the pet food companies that have taken the ingredient transparency pledge.