A Crossover Study of Noodle Soup Consumption in Melamine Bowls and Total Melamine Excretion in Urine

Melamine exposure remains common even after the 2008 melamine-tainted baby formula incident, which resulted in 6 deaths and approximately 50 000 hospitalizations.¹ A continuous low-dose melamine exposure has been linked to urolithiasis in both children and adults.^2- 3 Another source of melamine exposure is melamine tableware.⁴ In a pilot study, we asked 16 healthy volunteers (age range, 20-27 years) to consume 500 mL of hot noodle soup (initial temperature, 90°C) served in melamine bowls in the morning of October 2011. We collected from each participant 1 spot urine sample immediately before and at 2-hour intervals for 12 hours after consuming the noodle soup. This experiment simulated the natural situation; thus, not all participants provided urine samples at every 2-hour interval. However, all urine samples from all participants were collected after consumption for 12 hours. Postconsumption mean urinary melamine concentrations, corrected for urinary creatinine, initially increased sharply, peaked at 4 to 6 hours, and then declined sharply for 2 hours and then less steeply for the remainder of the monitoring period (eFigure 1). We therefore investigated if consumption of hot noodle soup served in melamine bowls would increase total urinary melamine excretion.