I googled melamine and the molecule gives off ammonia when it breaks down, which is what makes it toxic. The amine groups are what fools the test to think it's protein. The thing is, they wouldn't have to spike very much in to really boost the apparent protein level. This reinforces the "greed factor". I think this junk has been spiked in for a long time, but at subtoxic levels. There are relatively cheap on-line tests which can detect melemine because it has kind of a "special" structure.