Lots of us knew melamine as a heat resistant plastic polymer found in kitchen items, like plastic plates. Despite its reputation for heat resistance it would melt in an oven, although it doesn’t catch fire. It is used in a lot of other places: floor tiles, white boards, fabrics, filters, even the cleaning product called Magic Eraser. Now we know it is also used by crooked Chinese food manufacturers to make it appear their products have more protein than they really do. This works because melamine is loaded with nitrogen, also a key atom in the building blocks of proteins, amino acids.
Here is the atomic structure of melamine, whose official chemical name is 1,3,5-triazine-2,4,6-triamine:
The triazine part is the ring that has the three N’s in it. The ring is really composed of 6 atoms, the three Nitrogens shown by the N’s, and three carbons. The C’s for carbon are not shown here, a common convention. They would be at the alternate spots on the ring. If you start numbering the ring from the top, clockwise around the ring, you will find the Nitrogen atoms at the 1, 3 and 5 positions, with the suppressed carbons at the 2, 4 and 6 positions. Attached to each of these carbons is an amino group, -NH2, hence, 2, 4, 6 triamine. It’s quite a pretty little molecule and very symmetrical.
Every amino acid building block of a protein also has an amine group (-NH2), and assays that estimate protein by nitrogen content would identify melamine containing food as high protein:
For years, producers of animal feed all over China have secretly supplemented their feed with the substance, called melamine, a cheap additive that looks like protein in tests, even though it does not provide any nutritional benefits, according to melamine scrap traders and agricultural workers here.
“Many companies buy melamine scrap to make animal feed, such as fish feed,” said Ji Denghui, general manager of the Fujian Sanming Dinghui Chemical Company, which sells melamine. “I don’t know if there’s a regulation on it. Probably not. No law or regulation says ‘don’t do it,’ so everyone’s doing it. The laws in China are like that, aren’t they? If there’s no accident, there won’t be any regulation.” (New York Times)
The current alarm over melamine involves its addition to wheat gluten, a protein used in pet food and from there, sometimes given to livestock. Some US pork products are said to be contaminated with small quantities of melamine. Over 10,000 reports of sick pets in the US have been attributed to contaminated pet food, and melamine is the most mentioned culprit as the cause of their renal failure. It is not at all clear how melamine causes damage and it is generally thought that some metabolite of the resin is the active agent (see a brief summary of current ideas in the wikipedia article on melamine, which appears reliable). The small amounts of melamine that might find its way into the human food chain (e.g., the pork route) are unlikely to be a public health risk in itself, but it illustrates two things: how readily contaminants move through the highly connected network that is industrial food production; and the almost complete lack of oversight and protection by the US Food and Drug Administration. Harmful or not, this is adulterated food. And by all accounts, the adulteration by Chinese producers is widespread and has been going on for years.
So there’s melamine that’s not supposed to be in our food. What else?