The pet food recall began in March 2007 and to this date is the largest recall ever known in history. At first the focus was mainly Menu Foods. It then spread to Royal Canine Canada, Alpo Purina, Hill’s Prescription Diet, Iam’s, and the list goes on and on. All in all more than 5300 pet food products were recalled.

Pets began exhibiting illness in the form of urinary difficulties. Some abruptly died from the contamination and some will be sick forever. By April 2007 approximately 3600 pet deaths had been reported. This came from an online database as there is no centralized government records database of pet death and as such, the full extent of pet illness and deaths may never be known. Veterinarians’ offices were flooded with massive amounts of calls and told pet owners to bring in the pet if it exhibited any sign of illness.

There were also at least 90 class action lawsuits proposed against Menu Foods for fraud, who offered to pick up the vet’s tab if it could be proved that the illness came from the recalled foods. Their plants in Canada were promptly inspected. Pet owners were extremely worried and with the deaths of their pets, grief stricken. The public became outraged and calls went out for government regulation of pet foods.

The initial focus was on aminopterin which is commonly used in rat poison. It was then found that a Chinese company was to blame, adding melamine to the food and exporting it to the United States. It was found in the wheat gluten, rice protein concentrate, and corn gluten used to thicken the gravy style pet foods. Large amounts had been found in the food.

Melamine is used to make plastics, cleaning products, and fertilizers. The result of this addition was believed to cause acute kidney failure. The melamine causes urinary crystals to form which can block the urethras leading to the kidneys. The symptoms include lethargy, depression, and loss of appetite, vomiting, diarrhea, changes in water consumption, and changes in urination. Cats were found to be much more sensitive to the contamination than dogs. However this was a puzzle because melamine alone was not shown to cause kidney failure and is usually excreted in the urine.

Then a second contaminant was found, cyanuric acid, a chemical used in pool chlorination. The cyanuric acid and melamine were found in experiments to act together increasing each other’s potency. Owners began cooking and feeding natural and raw foods such as chicken and rice to their pets. Sales of natural pet diet foods and books on how to cook them went through the roof. The Chinese denied any alterations to the pet food.

One interesting note: Our inspectors headed to China to inspect the factory that had produced the pet food. When they arrived they discovered the factories had been closed. The melamine that had been fed to other animals such as chickens was feared to have spread to the human population; the government quickly announced that it would cause no damage to humans.