Melamine is known to many people as a type of dinnerware, the hard plastic material used to make colorful plates and trays for picnics and camping. Now, with recent headlines detailing the pet food recall, the public has learned another thing about melamine -- it is toxic when eaten.
Melamine is primarily used in the manufacture of hard resins, as for kitchenware. It is also used as a fertilizer in Asia, but is not approved for this use in the United States.1
The hard plastic that is familiar to many in the United States is created by polymerization (process of combining individual molecules into chains) of melamine and formaldehyde. The end product is known as melamine resin and is used in kitchenware, floor and counter laminates, ready-to-assemble furniture among other common household items.
Ingestion of melamine in animal studies has shown that clinical signs may include: cancer, kidney stones or reproductive damage.2 Melamine as a single agent has low toxicity; veterinary officials are not sure yet how this is causing such severe symptoms (kidney failure) and death. The role of the toxic agent first identified by the New York State Agriculture and Markets Food Laboratory, aminopterin, is also unclear, as neither Cornell nor the FDA could confirm the presence of aminopterin in food samples.3
Aminopterin has been associated with wheat gluten. Melamine has been associated with rice protein concentrate. Neither melamine nor aminopterin have any known use in food manufacturing and the source of contamination remains a mystery. Many people, including the FDA, are now suspicious of intentional contamination somewhere along the line.4 "Somebody may have added melamine to the wheat gluten in order to increase what appears to be the protein level," the FDA's Stephen Sundlof told CNN on Friday."
Since the start of this tragedy, people have wondered if human foods have also been contaminated. News reports insist that everything is safe, but with new information being released daily, it is hard to be sure. About.com Guide to Chemistry, Anne Marie Helmenstine, Ph.D., answers the question: "Is Contaminated Wheat Gluten in Human Foods?"
1 Melamine: The Chemical Found in Recalled Pet Food
2Chemical Sampling Information Melamine
3No Aminopterin in Tissues of Animals Killed by Recalled Pet Food
4One possibility: Pet food adulterated on purpose