Melamine Toxicity Clarified And New Test Developed

In 2008, infant formula intentionally doctored with the toxic compound melamine to fraudulently boost apparent protein content sickened an estimated 300,000 babies in China and killed six from kidney damage. Two new reports each address a different question that arose in the scandal’s wake: how melamine toxicity occurs, and how to rapidly and cheaply detect it in foods. A team led by Aihua Zhao and Wei Jia of China’s Shanghai Jiao Tong University investigated the role of intestinal bacteria in melamine toxicity (Sci. Transl. Med., DOI: 10.1126/scitranslmed.3005114). They determined that Klebsiella terrigena can convert melamine to cyanuric acid in the intestines of rats. The two compounds aggregate through hydrogen bonding and precipitate in the kidney, causing damage. Meanwhile, Xiaoya Hu of China’s Yangzhou University and colleagues have developed an assay that detects subnanomolar melamine in infant formula powders (J. Agric. Food Chem., DOI: 10.1021/jf304034e). Safety agencies test milk-based products for melamine, but most techniques require sophisticated instruments. Hu’s team first oxidizes melamine electrochemically. The oxidized melamine grafts to an electrode. Then the team couples the enzyme horseradish peroxidase to the grafted melamine. They dip the combination electrode into a solution, forming a colored product measurable with a spectrophotometer.