
Last week, the U.S. Food and Drug Administration (FDA) reported that thousands of farm animals across the country have eaten melamine, a nitrogen-rich chemical used in plastics, fertilizers, industrial binding agents, cookware and flame retardants. The pork and poultry poisonings followed the March 2007 recall of some 60 million containers of wet pet food from retail stores across North America. In the case of the pet food recall, the New York State Department of Agriculture & Markets quickly placed the blame on aminopterin, a chemical used in cancer drugs and rat poison. Further studies revealed the presence of melamine in both pet food and farm-animal feed. What's going on here? The Y Files will try to answer some questions.
Why Did They Do It?
Scientists speculate that the Chinese companies which laced their animal feeds with melamine did so for financial gain. "Animal food products," explains Gary Weaver, a veterinary pathologist at the University of Maryland, "are really priced on their protein content". Like the amino acids in proteins, melamine is nitrogen-rich. Moreover, tests for protein cannot distinguish the nitrogen in amino acids from the nitrogen in melamine. Although farm animals get "no benefit from the melamine whatsoever," Weaver claims, melamine is not particularly toxic. In fact, a 1945 study which administered large does of melamine to dogs reported only increased rates of urination.
Why Are We Worried?
If melamine is not especially toxic, and if unscrupulous companies have been adding it to animal feed for years, why are we worried now? According to Perry Martos, a chemist at the University of Guelph in Ontario, there's more to the pork and poultry poisonings than melamine. Recently, Martos analyzed the urine and kidneys of affected animals and identified the presence of not only melamine, but cyanuric acid – a chemical added to swimming pools to prevent the breakdown of chlorine. Martos and Grant Maxie, director of the University of Guelph's Animal Health Laboratory, theorize that this combination of melamine and cyanuric acid is deadly. Together, these chemicals can form a solid "super-molecular aggregate" that creates stones large enough to block an animal's urinary tract.
Where Did It Come From?
So where does the cyanuric acid in animal feed come from? According to Martos, it's unlikely that melamine breaks down into cyanuric acid within an animal's body. If this was the case, animals would have died from these "two smoking guns" long before the winter of 2006 - 2007. According to Bruce Akey, executive director of Cornell's Animal Health Diagnostic Center, the problem may be a contaminated contaminant. The cheap, crude melamine that Chinese companies used may be laced with nitrogen-laden chemical such as cyanuric acid. Alternatively, this melamine may have been of such poor quality that it began to break down long before its ingestion by animals.
Resources:
http://www.livescience.com/humanbiology/070502_pet_food.html
http://www.sciam.com/article.cfm?articleID=2B10D1F6-E7F2-99DF-34DAAAC1622FE3CE&chanID=sa007
Steve Melito - The Y Files
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