Pet food facts and fallacies (Sponsored by Nestle Purina)


Pet owners often use their veterinarians as a resource on pet foods.

A Web search query for pet foods returns millions of hits. Many sites offer sound advice, but numerous others provide incorrect or misleading information. Pet owners often use their veterinarians as a resource on pet foods. An awareness of the facts surrounding the more common issues is important to effectively communicate on these matters with clients.

What's AAFCO?

The acronym AAFCO commonly appears on dog and cat food labels. However, few in the public understand the nature and role of the Association of American Feed Control Officials in pet food regulation or, in fact, even know what the acronym stands for (Table 1). Many assume AAFCO is the regulatory overseer of the industry or a certifying body that tests pet foods to ensure that they meet nutritional and other standards. Others believe AAFCO is a trade association or otherwise caters to the pet food industry's interests.

Table 1. Common misinterpretations of the acronym AAFCO (Association of American Feed Control Officials) on pet food Web sites

In fact, AAFCO is a private organization that has no regulatory powers. It does no product testing, nor does it otherwise exercise authority over the production or sale of pet foods. Rather, these functions are performed by the U.S. Food and Drug Administration (FDA) and individual state governments. While AAFCO is not a government agency, all of its members are federal, state, and foreign government officials.1 Essentially, its role is to set standards that represent a consensus among regulators as to what constitutes the appropriate regulation of animal feed. This includes the AAFCO Model Bill and Regulations and other guidance that state agencies are then free to adopt and enforce as their own rules.

Representatives of outside groups can provide information to committees and working groups within AAFCO and are free to voice their opinions at public AAFCO meetings. While pet food trade associations are always well represented, consumer and veterinary representitives are also free to attend and participate in discussions. The important fact is that these non-government representatives are not allowed to be members of AAFCO and, hence, cannot hold office, make motions, or cast votes on any matter. Therefore, all actions taken by AAFCO are from the point of view of regulators, not industry.

Nutritional adequacy substantiation methods

In the early 1990s, a panel comprising experts from academia and industry and chaired by an FDA veterinary nutritionist were asked to develop a proposal to replace the National Research Council recommendations as the basis for substantiating the nutritional adequacy of pet foods. The result of the panel's deliberation was the AAFCO Dog and Cat Food Nutrient Profiles. The panel also recommended revision to AAFCO feeding trial protocols during that period. The recommendations of the panel were subsequently passed by the Pet Food Committee, the board of directors, and the full membership of AAFCO.

Veterinarians are often taught that the nutritional adequacy of pet foods is better substantiated by feeding trials than by reliance on meeting a set of nutrient standards such as the profiles. In reality, both methods provide reasonable assurances of nutritional adequacy, but each method has its advantages and disadvantages (Table 2).2

Table 2. AAFCO methods for nutritional adequacy substantiation of pet foods

The biggest issue with the feeding trial method is that many pet foods bearing an animal feeding tests statement on the label are never tested in the manner suggested by the claim. Under a third but rarely discussed "product family" option, the results of a single feeding trial can be used to support claims of nutritional adequacy for a number of distinct products. This option is allowed as long as the product family members meet provisions for nutrient and calorie content similar to those of a product actually tested. However, there are no restrictions on ingredient substitutions, so the equivalency of nutrient bioavailability compared with that of the tested product cannot be assured. Further, the nutritional adequacy statement on the product family member label misleadingly suggests it was fully tested for nutritional adequacy, when in fact it was only subject to a 10-day digestibility trial in order to calculate and compare caloric content with the tested product. Thus, the product family option is the least reliable means of substantiating nutritional adequacy, though perhaps the most common for pet foods bearing the feeding tests statement.

While both methods have their pros and cons, the feeding trial and nutrient profile methods tend to make up for each other's deficiencies. Thus, while AAFCO only requires one or the other, the best assurance of nutritional adequacy is if both methods are employed. Most products declaring substantiation by the feeding trial criteria also meet the nutrient profiles, but that latter fact rarely appears on the label. On the other hand, a pet food label bearing a claim of substantiation by the nutrient profile method is less likely to have been tested by feeding trials. Interestingly enough, some companies are presently declaring substantiation by the nutrient profile method even when feeding trials were conducted, assumedly in response to concerns by animal rights advocates.

Misconceptions about pet food ingredients

By law, pet food ingredients must be approved food additives, generally recognized as safe (GRAS) or otherwise sanctioned for use in pet food. A new ingredient must be reviewed for safety by FDA before it can be listed in the AAFCO Official Publication.

Often, self-appointed consumer advocates will attack the safety or value of a pet food ingredient based on little pertinent data but much speculation and innuendo. This situation occurred with the antioxidant preservative ethoxyquin in the early 1990s.3 Consumer concerns stemmed from ethoxyquin's use in pet food products and ranged from anecdotal reports of increases in allergic conditions and congenital abnormalities to a higher incidence of various cancers. While FDA has never revoked ethoxyquin's food additive status (FDA recommended—but did not require—a reduced maximum use level in dog foods), most manufacturers removed ethoxyquin from their formulations because of public pressure.

Meat by-products

The term meat by-products connotes all sorts of unappealing perceptions, even though the category includes parts of animals people eat themselves, such as livers, intestinal casings, thymus, kidneys, brains, and blood. Other types of meat by-products may include animal parts people do not eat, such as lungs, spleens, udders, and bone. Either way, AAFCO definitions specify that these ingredients must be derived from the clean parts of slaughtered animals—not parts taken from 4D (dead, dying, diseased, or disabled) animals or contaminated by filth.1

Corn and wheat

As far as potential allergenicity, corn and wheat are often criticized as being more allergenic than other grains such as rice. The historical use of rice in therapeutic diets as a novel ingredient for the diagnosis or control of food allergies may have led to this false impression. In cases in which the cause of a food allergy has been determined, the incidence of allergy to corn is equivalent to the incidence of allergy to rice.4 The highly reported recall of pet foods in 2007 was initially attributed to the contamination of wheat gluten with melamine and related compounds, which led to great disparagement of this ingredient.5 In fact, the adulterated ingredient was not wheat gluten but was wheat flour that was intentionally spiked with a non-protein nitrogen source to falsely elevate apparent protein levels. This illegal act does not diminish the utility of wheat gluten, other wheat products, or other sources of gluten.

Other misunderstandings

Many opponents of the pet food industry cite existing AAFCO definitions as proof of unsuitable materials in pet foods. Granted, some of the names evoke unpleasant reactions, such as restaurant food waste (AAFCO #60.97), dried poultry litter (AAFCO #74.3) and unborn calf carcasses (AAFCO #9.67).1 Properly processed, these ingredients may be useful in animal feeding (e.g. poultry litter as a source of nonprotein nitrogen and fiber to ruminants), but simply have no use in pet foods. Regardless, what opponents fail to note is that if these ingredients were in a pet food, by law they would have to be declared on the label by their official AAFCO names.

Opponents also frequently assert the presence of dog and cat carcasses in pet foods. It is true that the rendering of euthanized dogs and cats has been used as a means of disposal. However, there are many other uses for rendered materials other than pet food and the source of rendered material determines whether the material contains pet carcasses (e.g. a dead animal pick-up service vs. a slaughterhouse-dedicated plant). So, there is no incentive for pet food companies to use rendered products that may contain these materials. Still, regulators cannot unequivocally confirm that these materials are never used. The FDA conducted an analysis of numerous pet foods and posted these results on its Web site.6 Trace amounts of pentobarbital have been found in some pet foods, although only at levels well below what would have any physiologic effect on an animal consuming the product. Some products with residues did not contain ingredients that would be likely sources of pentobarbital, so FDA could not fully explain its findings. Regardless, samples were also analyzed for dog- or cat-specific proteins, and no evidence could be found of any dog or cat material in any pet food.

Pet food terms

Pet food purchasers are barraged with a plethora of marketing terms on pet food labels. Some terms have regulatory definitions while others have no real meaning.

"Natural" foods

Many pet owners assume a "natural" pet food contains better ingredients and is hence safer than conventional pet foods. By AAFCO definition, a natural product essentially excludes all ingredients that are chemically synthetic.1 However, complete and balanced pet foods often rely on synthetic trace nutrients such as vitamins, minerals, and taurine; hence, these foods must be qualified by a disclaimer, for example, "natural with added...." The ingredients in natural pet foods and conventionally formulated pet foods are largely the same. One difference is that the former may not contain chemically synthetic nonnutritive ingredients, such as artificial preservatives, flavors, or colors except in amounts that may be unavoidable through good manufacturing practices. There is little scientific basis to show that natural products are safer, healthier, or more nutritious. In fact, some researchers have questioned the ability of natural preservatives to prevent product degradation as effectively as synthetic preservatives, which if true could lead to spoilage, loss of nutritive value, and potential adverse effects.4

Organic pet foods

Organic is not the same as natural, but rather describes a whole system of production, manufacturing, and handling of ingredients and products. The requirements are codified in the U.S. Department of Agriculture's National Organic Program (NOP) regulations. However, these rules are not considered by NOP as a means to ensure safer, healthier, or more nutritious foods. Rather, the organic label is viewed as a confirmation of the organic production process, and the purchaser is left to his or her own determination as to whether the costs merit the perceived benefits.

"Premium" pet foods

Notwithstanding its consumer appeal, there are no regulatory definitions or standards for premium, super premium, or holistic pet food above or beyond any other pet food. Thus, use of these terms on labels has no effective meaning.


Understanding the issues surrounding pet food manufacturing and regulation is a daunting task. Many resources are available to help, but separating fact from fiction can be a challenge.

David A. Dzanis, DVM, PhD, DACVN

Regulatory Discretion, Inc.

16256 Ravenglen Road

Santa Clarita, CA 91387


1. AAFCO Official Publication. Oxford, Ind: Association of American Feed Control Officials, 2009.

2. Dzanis DA. Ensuring nutritional adequacy. In: Kvamme JL, Phillips TD, eds. Petfood Technology. Mt. Morris, Ill: Watt Publishing, 2003;62-67.

3. Dzanis DA. Safety of ethoxyquin in dog foods. J Nutr 1991;121(11 Suppl):s163-164.

4. Cowell CS, Stout NP, Brinkmann MF, et al. Making commercial pet foods (ingredient myths and facts). In: Hand MS, Thatcher CD, Remillard RL, et al., eds. Small Animal Clinical Nutrition, 4th ed. Topeka, Kan: Mark Morris Institute, 2000;127-146.

5. Melamine pet food recall - frequently asked questions. [Online]. Available: Accessed: Dec. 17, 2009.

6. Food and Drug Administration/Center for Veterinary Medicine report on the risk from pentobarbital in dog food [Online]. Available: Accessed: Dec. 17, 2009.

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