Melamine: a brief journey from animal feed to cow's milk

Abstract

Melamine is a triazine compound containing 66.6% nitrogen. It is utilised in various industrial applications, including the production of plastics, adhesives, and fertilisers. However, melamine can also contaminate food and animal feed, as it is sometimes added to artificially enhance protein content, which can be toxic to both animals and humans. Notable food contamination incidents involving melamine include the 2007 pet food scandal and the 2008 melamine-contaminated milk scandal in China, which resulted in serious kidney damage and fatalities, particularly among children. The primary health risks associated with melamine arise from its ability to form crystals in the kidneys, potentially leading to renal failure. The body rapidly absorbs and excretes melamine, primarily through urine, as metabolism is minimal. Although acute doses are relatively low in toxicity, long-term exposure, especially through contaminated food, can pose significant health threats. In response to the melamine-related health crises in China, the WHO and EFSA established safe intake levels of 0.2 mg/kg/day for melamine and 1.5 mg/kg/day for cyanuric acid. Various countries have set maximum residue limits for melamine in food, with the United States and China permitting 1.0 mg/kg for infant formula and 2.5 mg/kg for other dairy products. In Europe, the limits are stricter, at 1.0 mg/kg for powdered infant formula, 0.1 mg/kg for liquid formula, and 2.5 mg/kg for foods. The determination of melamine and cyanuric acid in food and feed presents significant challenges. Advanced techniques such as high-performance liquid chromatography and tandem mass spectrometry are the most commonly employed methods.