SHANGHAI, May 8 — A second industrial chemical that American regulators have identified as a pet food contaminant may have been intentionally added to animal feed by producers seeking larger profits, according to interviews Tuesday with chemical industry officials.
Three chemical makers said Chinese animal feed producers often came to purchase cyanuric acid to blend into their feed because it was cheaper and helped increase protein content. In the United States, cyanuric acid is often used as a chemical stabilizer in swimming pools, though it is not thought to be highly toxic on its own.
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Two of the Chinese chemical makers say that cyanuric acid is used because it is even cheaper than melamine and high in nitrogen, enabling feed producers to artificially increase protein readings which are often measured by nitrogen levels of the feed. The chemical makers say they also produce a chemical which is a combination of melamine and cyanuric acid, and that feed producers have often sought to purchase scrap material from this product.
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Scientists had difficulty pinpointing the precise cause of the deaths, for neither melamine nor cyanuric acid are thought to be particularly toxic by themselves. But scientists studying the pet food deaths say the combination of the two chemicals, mixed together with perhaps some other related compounds, may have created a toxic punch that formed crystals in the kidneys of pets and led to kidney failure.
The article goes on to say that scientists at the University of Guelph in Canada had on May 1 announced that by mixing melamine and cyanuric acid they were anle to create crystals similar to the crystals "found in afflicted pets."
More detais at:
http://www.nytimes.com/2007/05/09/business/worldbusiness/09food.html