ZOSIMO T. LITERATUS, RMTTwo outbreaks of petfood-associated renal failure occurred in 2004 (involving around 6,000 dogs and a smaller number of cats) and 2007 (involving a large number of dogs and cats in North America). In 2004, the outbreak was linked to the ingestion of specific commercial dog foods, and occurred in dogs from Asia. Health authorities attributed it to poisonous compounds (particularly ochratoxin, citrinin, or both) that contaminated raw materials in a manufacturing plant in Thailand.
In 2007, on the heel of another renal failure outbreak associated with pet foods, North American health authorities identified the toxic compounds as melamine and cyanuric acid; both are present in wheat gluten, rice protein, and corn gluten imported from China and used as a pet food ingredient. Able to elevate falsely the measure of protein content in pet foods because of its high nitrogen content, melamine was presumed to have been intentionally added by suppliers in China.
Two studies, in 1945 (WL Lipschitz & E Stokey) and 1984 (Melnick, Boorman, Haseman, et al), agreed that melamine alone does not cause renal failure in dogs and rodents. However, together with cyanuric acid, Tom McPheron (+17734945419) of the American Veterinary Medical Association observed that melamine form insoluble crystals that obstruct and damage renal tubules and are presumed to cause renal failure. Researchers from the University of Pennsylvania confirmed this finding in their own study[1] published in the Journal of American Veterinary Medical Association on September 1.
Despite these findings, two leading American government agencies (the Food and Drug Authority and the Department of Agriculture) deemed melamine a very low human risk due to limited information available at that time…of course, until another outbreak happened.
This time, the outbreak of acute renal failure involved children who consumed adulterated milk in China. Four infant died and thousands got hospitalized from melamine, as reported, in milk and infant formulas. While the presence of melamine has been covered well in these products, no mention of cyanuric acid has been made so far. The sudden spurt of this outbreak left health observers doubting any cumulative basis for such a tragedy. It must be a high level of melamine and cyanuric acid in these products taken within a short period of time.
In 2007, on the heel of another renal failure outbreak associated with pet foods, North American health authorities identified the toxic compounds as melamine and cyanuric acid; both are present in wheat gluten, rice protein, and corn gluten imported from China and used as a pet food ingredient. Able to elevate falsely the measure of protein content in pet foods because of its high nitrogen content, melamine was presumed to have been intentionally added by suppliers in China.
Two studies, in 1945 (WL Lipschitz & E Stokey) and 1984 (Melnick, Boorman, Haseman, et al), agreed that melamine alone does not cause renal failure in dogs and rodents. However, together with cyanuric acid, Tom McPheron (+17734945419) of the American Veterinary Medical Association observed that melamine form insoluble crystals that obstruct and damage renal tubules and are presumed to cause renal failure. Researchers from the University of Pennsylvania confirmed this finding in their own study[1] published in the Journal of American Veterinary Medical Association on September 1.
Despite these findings, two leading American government agencies (the Food and Drug Authority and the Department of Agriculture) deemed melamine a very low human risk due to limited information available at that time…of course, until another outbreak happened.
This time, the outbreak of acute renal failure involved children who consumed adulterated milk in China. Four infant died and thousands got hospitalized from melamine, as reported, in milk and infant formulas. While the presence of melamine has been covered well in these products, no mention of cyanuric acid has been made so far. The sudden spurt of this outbreak left health observers doubting any cumulative basis for such a tragedy. It must be a high level of melamine and cyanuric acid in these products taken within a short period of time.
What compounds the puzzle is that melamine becomes undetectable in rat tissues merely 24 hours after exposure, making timing a critical factor in detecting this chemical in laboratory animals.
The British Medical Journal (BMJ) reported 6,200 babies hospitalized as of its September 18 issue. A week later, a similar report from BMJ indicated almost 13,000 babies got hospitalized for the renal failure outbreak.
Melamine (1,3,-triazine-2,4,6-triamine) is an industrial chemical used as a plastic resin and is known for its fire-retardant properties. A biochemical study in 1982 by Kathrin Jutzi, Alasdair Cook, and Ralf Hutter of the Microbiological Institute of the Swiss Federal Institute of Technology Zurich in Zurich, Switzerland, and published in the Biological Journal in Great Britain observed that melamine can be degraded by bacteria (e.g. Pseudomonas species and Klebsiella pneumoniae) into a by-product called ammelide, which in turn gets converted into cyanuric acid. This would explain the occurrence of renal failure among those who consumed foods contaminated with melamine, even if there has been no cyanuric acid was added in the product initial.
The British Medical Journal (BMJ) reported 6,200 babies hospitalized as of its September 18 issue. A week later, a similar report from BMJ indicated almost 13,000 babies got hospitalized for the renal failure outbreak.
Melamine (1,3,-triazine-2,4,6-triamine) is an industrial chemical used as a plastic resin and is known for its fire-retardant properties. A biochemical study in 1982 by Kathrin Jutzi, Alasdair Cook, and Ralf Hutter of the Microbiological Institute of the Swiss Federal Institute of Technology Zurich in Zurich, Switzerland, and published in the Biological Journal in Great Britain observed that melamine can be degraded by bacteria (e.g. Pseudomonas species and Klebsiella pneumoniae) into a by-product called ammelide, which in turn gets converted into cyanuric acid. This would explain the occurrence of renal failure among those who consumed foods contaminated with melamine, even if there has been no cyanuric acid was added in the product initial.
Possible presence of microorganisms in these products may have degraded some of the melamine into cyanuric acid, causing the well-documented crystal formation that resulted eventually to renal failure.
A Study on rats and pigs[2], reported at the Regulatory and Toxicological Pharmacology (Aug 2008), indicated that a single ingestion of melamine-contaminated pet feed at a dose of 3.0 and 5.12 mg melamine/kg body weight requires 19.2 and 20.9 hours, respectively, before the animal meat (pork) can be safely eaten. Long-time exposure of the same dose for 7 days needs an hour longer before the pork can be consumed without potential harm.
The detection of melamine and cyanuric acid from the proteins in wheat, rice, and corn is something that Philippine health and food authorities--the Departments of Health and of Agriculture--needs to look into, or at least ensure that such chemicals cannot be detected in our country-grown cereals. If they fail to do this, then we may as well hope that outbreaks from the melamine-cyanuric acid combination will not happen among our own people and pets, or at least not as widespread as what happened in China.
In short, contamination of milk, milk-products and pet foods are mere outcomes of an often unnoticed source of poisonous chemicals--our very source of daily staples: rice and corn (we don't use wheat that much in our meals). If we are not careful enough to test locally grown and imported rice, for example, we might as well wear a badge with the caption: "Why Am I So Stupid!"
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Notes:
[1] Cianciolo RE, Bischoff K, Ebel JG, Van Winkle TJ, Goldstein RE, Serfilippi LM of the Dept of Pathology and Toxicology of the School of Veterinary Medicine at the University of Pennsylvania observed that renal failure already can be observed within 7 to 11 days after consumption of pet food contaminated with melamine and cyanuric acid.
[2] By JL Buur (jbuur@westernu.edu), RE Baynes, and JE Riviere of the Food Animal Residue Avoidance Databank of the Center for Chemical Toxicology Research and Pharmacokinetics at the North Carolina State University, College of Veterinary Medicine in Raleigh, North Carolina.
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