Plump whole chickens, choice cuts of beef, fresh grains, and all the wholesome nutrition your dog or cat will ever need. When it comes to pet food ingredients, do you know what’s really in pet food?
These are the images pet food manufacturers promulgate through the media and advertising. This is what the $11 billion per year U.S. pet food industry wants consumers to believe they are buying when they purchase their products.
This report explores the differences between what consumers think they are buying and what they are actually getting. It focuses in very general terms on the most visible name brands — the pet food labels that are mass-distributed to supermarkets and discount stores — but there are many highly respected brands that may be guilty of the same offenses.
What most consumers don’t know is that the pet food industry is an extension of the human food and agriculture industries. Pet food provides a market for slaughterhouse offal, grains considered “unfit for human consumption,” and similar waste products to be turned into profit. This waste includes intestines, udders, esophagi, and possibly diseased and cancerous animal parts.
Three of the five major pet food companies in the United States are subsidiaries of major multinational companies: Nestlé (Alpo, Fancy Feast, Friskies, Mighty Dog, and Ralston Purina products such as Dog Chow, ProPlan, and Purina One), Heinz (9 Lives, Amore, Gravy Train, Kibbles-n-Bits, Nature’s Recipe), Colgate-Palmolive (Hill’s Science Diet Pet Food). Other leading companies include Procter & Gamble (Eukanuba and Iams), Mars (Kal Kan, Mealtime, Pedigree, Sheba, Waltham’s), and Nutro. From a business standpoint, multinational companies owning pet food manufacturing companies is an ideal relationship. The multinationals have increased bulk-purchasing power; those that make human food products have a captive market in which to capitalize on their waste products, and pet food divisions have a more reliable capital base and, in many cases, a convenient source of ingredients.
There are hundreds of different pet foods available in this country. And while many of the foods on the market are similar, not all of the pet food manufacturing companies use poor quality or potentially dangerous ingredients.
Although the purchase price of pet food does not always determine whether a pet food is good or bad, the price is often a good indicator of quality. It would be impossible for a company that sells a generic brand of dog food at $9.95 for a 40-lb. bag to use quality protein and grain in its food. The cost of purchasing quality ingredients would be much higher than the selling price.
The protein used in pet food comes from a variety of sources. When cattle, swine, chickens, lambs, or other animals are slaughtered, the choice cuts such as lean muscle tissue are trimmed away from the carcass for human consumption. However, about 50% of every food-producing animal does not get used in human foods. Whatever remains of the carcass — bones, blood, intestines, lungs, ligaments, and almost all the other parts not generally consumed by humans — is used in pet food, animal feed, and other products. These “other parts” are known as “by-products,” “meat-and-bone-meal,” or similar names on pet food labels.
The Pet Food Institute — the trade association of pet food manufacturers — acknowledges the use of by-products in pet foods as additional income for processors and farmers: “The growth of the pet food industry not only provided pet owners with better foods for their pets, but also created profitable additional markets for American farm products and for the byproducts of the meat packing, poultry, and other food industries which prepare food for human consumption.” 1
Many of these remnants provide a questionable source of nourishment for our animals. The nutritional quality of meat and poultry by-products, meals, and digests can vary from batch to batch. James Morris and Quinton Rogers, two professors with the Department of Molecular Biosciences, University of California at Davis Veterinary School of Medicine, assert that, “There is virtually no information on the bioavailability of nutrients for companion animals in many of the common dietary ingredients used in pet foods. These ingredients are generally by-products of the meat, poultry and fishing industries, with the potential for a wide variation in nutrient composition. Claims of nutritional adequacy of pet foods based on the current Associationof American Feed Control Officials (AAFCO) nutrient allowances (‘profiles’)do not give assurances of nutritional adequacy and will not until ingredients are analyzed and bioavailability values are incorporated.” 2
Meat and poultry meals, by-product meals, and meat-and-bone meal are common ingredients in pet foods. The term “meal” means that these materials are not used fresh, but have been rendered. What is rendering? Rendering, as defined by Webster’s Dictionary , is “to process as for industrial use: to render livestock carcasses and to extract oil from fat, blubber, etc., by melting.” Home-made chicken soup, with its thick layer of fat that forms over the top when the soup is cooled, is a sort of mini-rendering process. Rendering separates fat-soluble from water-soluble and solid materials, removes most of the water, and kills bacterial contaminants, but may alter or destroy some of the natural enzymes and proteins found in the raw ingredients. Meat and poultry by-products, while not rendered, vary widely in composition and quality.
What can the feeding of such products do to your companion animal? Some veterinarians claim that feeding slaughterhouse wastes to animals increases their risk of getting cancer and other degenerative diseases. The cooking methods used by pet food manufacturers — such as rendering, extruding (a heat-and-pressure system used to “puff” dry foods into nuggets or kibbles), and baking — do not necessarily destroy the hormones used to fatten livestock or increase milk production, or drugs such as antibiotics or the barbiturates used to euthanize animals.
Animal and Poultry Fat
You may have noticed a unique, pungent odor when you open a new bag of pet food — what is the source of that delightful smell? It is most often rendered animal fat, restaurant grease, or other oils too rancid or deemed inedible for humans.
Restaurant grease has become a major component of feed grade animal fat over the last fifteen years. This grease, often held in fifty-gallon drums, may be kept outside for weeks, exposed to extreme temperatures with no regard for its future use. “Fat blenders” or rendering companies then pickup this used grease and mix the different types of fat together, stabilize them with powerful antioxidants to retard further spoilage, and then sell the blended products to pet food companies and other end users.
These fats are sprayed directly onto extruded kibbles and pellets to make an otherwise bland or distasteful product palatable. The fat also acts as a binding agent to which manufacturers add other flavor enhancers such as digests. Pet food scientists have discovered that animals love the taste of these sprayed fats. Manufacturers are masters at getting a dog or a cat to eat something she would normally turn up her nose at.
Wheat, Soy, Corn, Peanut Hulls, and Other Vegetable Protein
The amount of grain products used in pet food has risen over the last decade. Once considered filler by the pet food industry, cereal and grain products now replace a considerable proportion of the meat that was used in the first commercial pet foods. The availability of nutrients in these products is dependent upon the digestibility of the grain. The amount and type of carbohydrate in pet food determines the amount of nutrient value the animal actually gets. Dogs and cats can almost completely absorb carbohydrates from some grains, such as white rice. Up to 20% of the nutritional value of other grains can escape digestion. The availability of nutrients for wheat, beans, and oats is poor. The nutrients in potatoes and corn are far less available than those in rice. Some ingredients, such as peanut hulls, are used for filler or fiber, and have no significant nutritional value.
Two of the top three ingredients in pet foods, particularly dry foods, are almost always some form of grain products. Pedigree Performance Food for dogs lists Ground Corn, Chicken By-Product Meal, and Corn Gluten Meal as its top three ingredients.9 Lives Crunchy Meals for cats lists Ground Yellow Corn, Corn Gluten Meal, and Poultry By-Product Meal as its first three ingredients. Since cats are true carnivores — they must eat meat to fulfill certain physiological needs — one may wonder why we are feeding acorn-based product to them. The answer is that corn is a much cheaper “energy source” than meat.
In 1995, Nature’s Recipe pulled thousands of tons of dog food off the shelf after consumers complained that their dogs were vomiting and losing their appetite. Nature’s Recipe’s loss amounted to $20 million. The problem was a fungus that produced vomitoxin (an aflatoxin or “mycotoxin,” a toxic substance produced by mold) contaminating the wheat. In 1999, another fungal toxin triggered the recall of dry dog food made by Doane Pet Care at one of its plants, including Ol’ Roy (Wal-Mart’s brand) and 53 other brands. This time, the toxin killed 25 dogs.
Although it caused many dogs to vomit, stop eating, and have diarrhea, vomitoxin is a milder toxin than most. The more dangerous mycotoxins can cause weight loss, liver damage, lameness, and even death as in the Doane case. The Nature’s Recipe incident prompted the Food and Drug Administration (FDA) to intervene. Dina Butcher, Agriculture Policy Advisor for North Dakota Governor Ed Schafer, concluded that the discovery of vomitoxin in Nature’s Recipe wasn’t much of a threat to the human population because “the grain that would go into pet food is not a high quality grain.” 3
Soy is another common ingredient that is sometimes used as a protein and energy source in pet food. Manufacturers also use it to add bulk so that when an animal eats a product containing soy he will feel more sated. While soy has been linked to gas in some dogs, other dogs do quite well with it. Vegetarian dog foods use soy as a protein source.
Additives and Preservatives
Many chemicals are added to commercial pet foods to improve the taste, stability, characteristics, or appearance of the food. Additives provide no nutritional value. Additives include emulsifiers to prevent water and fat from separating, antioxidants to prevent fat from turning rancid, and artificial colors and flavors to make the product more attractive to consumers and more palatable to their companion animals.
Adding chemicals to food originated thousands of years ago with spices, natural preservatives, and ripening agents. In the last 40 years, however, the number of food additives has greatly increased.
All commercial pet foods must be preserved so they stay fresh and appealing to our animal companions. Canning is a preserving process itself, so canned foods contain less preservatives than dry foods. Some preservatives are added to ingredients or raw materials by the suppliers, and others may be added by the manufacturer. Because manufacturers need to ensure that dry foods have a long shelf life to remain edible after shipping and prolonged storage, fats used in pet foods are preserved with either synthetic or “natural” preservatives. Synthetic preservatives include butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), propyl gallate, propylene glycol (also used as a less-toxic version of automotive antifreeze), and ethoxyquin . For these antioxidants, there is little information documenting their toxicity, safety, interactions, or chronic use in pet foods that may be eaten every day for the life of the animal.
Potentially cancer-causing agents such as BHA, BHT, and ethoxyquin are permitted at relatively low levels. The use of these chemicals in pet foods has not been thoroughly studied, and long term build-up of these agents may ultimately be harmful. Due to questionable data in the original study on its safety, ethoxyquin’s manufacturer, Monsanto, was required to perform a new, more rigorous study. This was completed in 1996. Even though Monsanto found no significant toxicity associated with its own product, in July 1997, the FDA’s Center for Veterinary Medicine requested that manufacturers voluntarily reduce the maximum level for ethoxyquin by half, to 75 parts per million. While some pet food critics and veterinarians believe that ethoxyquin is a major cause of disease, skin problems, and infertility in dogs, others claim it is the safest, strongest, most stable preservative available for pet food. Ethoxyquin is approved for use in human food for preserving spices, such as cayenne and chili powder, at a level of 100 ppm– but it would be very difficult to consume as much chili powder every day as a dog would eat dry food. Ethoxyquin has never been tested for safety in cats.
Some manufacturers have responded to consumer concern, and are now using “natural” preservatives such as Vitamin C (ascorbate), Vitamin E (mixed tocopherols), and oils of rosemary, clove, or other spices, to preserve the fats in their products. Other ingredients, however, may be individually preserved. Most fish meal, and some prepared vitamin-mineral mixtures, contain chemical preservatives. This means that your companion animal may be eating food containing several types of preservatives. Federal law requires preservatives to be disclosed on the label; however, pet food companies only recently started to comply with this law.
Additives in Processed Pet Foods
- Anticaking agents
- Antimicrobial agents
- Coloring agents
- Curing agents
- Drying agents
- Firming agents
- Flavor enhancers
- Flavoring agents
- Flour treating agents
- Formulation aids
- Leavening agents
- Non nutritive sweeteners
- Nutritive sweeteners
- Oxidizing and reducing agents
- pH control agents
- Processing aids
- Solvents, vehicles
- Stabilizers, thickeners
- Surface active agents
- Surface finishing agents
While the law requires studies of direct toxicity of these additives and preservatives, they have not been tested for their potential synergistic effects on each other once ingested. Some authors have suggested that dangerous interactions occur among some of the common synthetic preservatives.