Leaching of melamine and cyanuric acid from melamine-based tableware at different temperatures and water-based simulants

Following food scandals involving melamine during 2007–2008, health risks from human exposure to this compound received worldwide attention. Since then several studies have reported sources of melamine exposure in humans. In this pilot study, leaching of melamine and cyanuric acid from melamine-based bowls was tested under normal cooking conditions. Four brands of melamine bowls (n = 10) were purchased randomly from among many similar products available in the market. Water-based simulants were used in leaching tests under four conditions; water at room temperature (25 °C), hot water (90–100 °C), 1% acetic acid in water (v/v), and 10% methanol in water (v/v). The concentrations of melamine leached from bowls were reported on the basis of the surface area that came in contact with the leaching solution. The highest concentration of melamine leached was 0.37–70.2 ng/cm2 found in hot water, followed by water at room temperature (<0.03–49.0 ng/cm2), 10% methanol/water (0.27–7.03 ng/cm2), and 1% acetic acid/water (0.20–6.54 ng/cm2). On the basis of the concentrations of melamine leached, daily intakes (EDIs) were calculated from the ingestion of water. In the high-exposure scenario, the EDIs of melamine reached up to 620 μg/kg bw/day for infants and these values were 1.24 times higher than the tolerable daily intake (TDI) established by the European Food Safety Authority (EFSA). Our study suggests that melamine-based tableware are a source of human exposure to this nephrotoxicant.