Harmful ingredients in pet food

Potential Contaminants

Given the types of things manufacturers put in pet food, it is not surprising that bad things sometimes happen. Ingredients used in pet food are often highly contaminated with a wide variety of toxic substances. Some of these are destroyed by processing, but others are not.

• Bacteria. Slaughtered animals, as well as those that have died because of disease, injury, or natural causes, are sources of meat, by-products, and rendered meals. An animal that died on the farm might not reach a rendering plant until days after its death. Therefore the carcass is often contaminated with bacteria such as Salmonella and E. coli. Dangerous E. Coli bacteria are estimated to contaminate more than 50% of meat meals. While the cooking process may kill bacteria, it does not eliminate the endotoxins some bacteria produce during their growth. These toxins can survive processing, and can cause sickness and disease. Pet food manufacturers do not test their products for bacterial endotoxins. Because sick or dead animals can be processed as pet foods, the drugs that were used to treat or euthanize them may still be present in the end product. Penicillin and pentobarbital are just two examples of drugs that can pass through processing unchanged. Antibiotics used in livestock production are also thought to contribute to antibiotic resistance in humans.
• Mycotoxins. Toxins from mold or fungi are called mycotoxins. Modern farming practices, adverse weather conditions, and improper drying and storage of crops can contribute to mold growth. Pet food ingredients that are most likely to be contaminated with mycotoxins are grains such as wheat and corn, and fish meal.
• Chemical Residue. Pesticides and fertilizers may leave residue on plant products. Grains that are condemned for human consumption by the USDA due to residue may legally be used, without limitation, in pet food.
• GMOs. Genetically modified plant products are also of concern. By 2006, 89% of the planted area of soybeans, 83% of cotton, and 61% of maize (corn) in the U.S. were genetically modified varieties. Cottonseed meal is a common ingredient of cattle feed; soy and corn are used directly in many pet foods.
• Acrylamide. This is a carcinogenic compound formed at cooking temperatures of about 250°F in foods containing certain sugars and the amino acid asparagine (found in large amounts in potatoes and cereal grains). It is formed in a chemical process called the Maillard reaction.^{4, 5} Most dry pet foods contain cereal grains or potatoes, and they are processed at high temperatures (200–300°F at high pressure during extrusion; baked foods are cooked at well over 500°F); these are perfect conditions for the Maillard reaction. In fact, the Maillard reaction is considered desirable in the production of pet food because it imparts a palatable taste, even though it reduces the bioavailability of some amino acids, including taurine and lysine.⁶ The content and potential effects of acrylamide formation in pet foods are unknown.

Pet Food Recalls

When things go really wrong and serious problems are discovered in pet food, the company usually works with the FDA to coordinate a recall of the affected products. While many recalls have been widely publicized, quite a few have not.

• In 1995, Nature’s Recipe recalled almost a million pounds of dry dog and cat food after consumers complained that their pets were vomiting and losing their appetite. The problem was a fungus that produced vomitoxin contaminating the wheat.
• In 1999, Doane Pet Care recalled more than a million bags of corn-based dry dog food contaminated with aflatoxin. Products included Ol’ Roy (Wal-Mart’s brand) and 53 other brands. This time, the toxin killed 25 dogs.
• In 2000, Iams recalled 248,000 pounds of dry dog food distributed in 7 states due to excess DL-Methionine Amino Acid, a urinary acidifier.
• In 2003, a recall was made by Petcurean “Go! Natural” pet food due to circumstantial association with some dogs suffering from liver disease; no cause was ever found.
• In late 2005, a similar recall by Diamond Foods was announced; this time the moldy corn contained a particularly nasty fungal product called aflatoxin; 100 dogs died.
• Also in 2005, 123,000 pounds of cat and dog treats were recalled due to Salmonella contamination.
• In 2006, more than 5 million cans of Ol’ Roy, American Fare, and other dog foods distributed in the southeast were recalled by the manufacturer, Simmons Pet Food, because the cans’ enamel lining was flaking off into the food.
• Also in 2006, Merrick Pet Care recalled almost 200,000 cans of “Wingalings” dog food when metal tags were found in some samples.
• In the most deadly recall of 2006, 4 prescription canned dog and cat foods were recalled by Royal Canin (owned by Mars). The culprit was a serious overdose of Vitamin D that caused calcium deficiency and kidney disease.
• In February 2007, the FDA issued a warning to consumers not to buy “Wild Kitty,” a frozen food containing raw meat. Routine testing by FDA had revealed Salmonella in the food. FDA specifically warned about the potential for illness in humans, not pets. There were no reports of illness or death of any pets, and the food was not recalled.
• In March 2007, the most lethal pet food in history was the subject of the largest recall ever. Menu Foods recalled more than 100 brands including Iams, Eukanuba, Hill’s Science Diet, Purina Mighty Dog, and many store brands including Wal-Mart’s. Thousands of pets were sickened (the FDA received more than 17,000 reports) and an estimated 20% died from acute renal failure caused by the food. Cats were more frequently and more severely affected than dogs. The toxin was initially believed to be a pesticide, the rat poison “aminopterin” in one of the ingredients. In April, scientists discovered high levels of melamine, a chemical used in plastics and fertilizers, in wheat gluten and rice protein concentrate imported from China. The melamine had been purposefully added to the ingredients to falsely boost their protein content. Subsequent tests revealed that the melamine-tainted ingredients had also been used in feed for cows, pigs, and chickens and thousands of animals were quarantined and destroyed. In early May, scientists identified the cause of the rapid onset kidney disease that had appeared in dogs and cats as a reaction caused by the combination of melamine and cyanuric acid, both unauthorized chemicals. The fallout from this recall is ongoing as of May 2007 so please be sure to check the FDA website for the most recent updates.