White Rabbit candies are being pulled from the shelves for failing to have less than 2.5 mg/kg melamine.
The Chinese press reported another 380 sick children in Beijing at the same time as they are declaring the milk safe. Though this seems to be a contradiction, my feeling is that stones in children will be showing up for months after the milk supply is clean as kidney stones can lie asymptomatic for months (years?) in the renal pelvis before spontaneously moving into the ureters where they cause pain, obstruction and hematuria.
The Taiwanese press provides a shockingly sophisticated article on the problems with our current toxicity knowledge of melamine and the associated debate on limits of safety. In addition to discuss limits of tolerability it goes into the differing methods of detection including high performance liquid chromatography (HPLC), liquid chromatography-tandem mass spectrometry (LC-MS/MS), gas chromatography-mass spectrometry (GC-MS). The LC-MS/MS method is apparently the most sensitive assay. One confusing aspect of the article is they swithc freely between mg/kg and ppm. One mg/kg is equal to 1 ppm.
A friend was staying with us over the week-end. She and her husband adopted a little girl from China. She was drinking chinese formula 6 months ago. She is doing well, no symptoms and when she came over she had a “kidney test.” The mother asked me if she should do anything. My answer was that her daughter likely was exposed to melamine as it looks like this practice of spiking milk with melamine has been going on for awhile. I added that since her daughter was doing well and not having colicky pain, a diagnosis of nephrolithiasis would not change what you do. I recommended against doing a renal ultra-sound and wait for any symptoms which would likely never occur.