FDA has released their safety analysis for human consumption of melamine — including scenarios that estimate human consumption of multiple sources.
But most surprisingly, it lists one sample source not mentioned before: bakery meal.
(UPDATE: Bakery meal is used for pets and was likely contaminated from tainted pet food being mixed into the batch.)
Bakery Meal Samples
As can be seen in Table A-2, to date, 27 samples of bakery meal thought to have been made with contaminated pet food have been collected and analyzed for all four compounds from four locations. Of those, 24 were negative for melamine. The three positive samples were from two different locations and contained concentrations of melamine from 10.6 to 59.6 ppm. Cyanuric acid was not detected in 15 of the samples, and ranged from 1.8 to 146.3 ppm in the other 12 samples. Nine samples had detectable levels of ammeline (Range of 1.2 to 24.9 ppm) and the other 18 samples were negative. Ammelide was detected in one sample (20.1 ppm) and the other 26 samples were negative.
The report does not look into the reaction between melamine and cyanuric acid and only mentions it briefly.
The report also says “the highest exposure estimate for the worst case scenario… is 252 times lower than the [Tolerable Daily Intake].”