It was a tragedy waiting to happen. By the time the first babies in China starting falling ill from milk powder adulterated with melamine, the Chinese and US authorities had been investigating the problem for over a year. That was in autumn 2008. Eighteen months previously, thousands of cats and dogs in the U.S. had already died from eating pet food containing contaminated protein powder from China. Given such suffering, it was an immense relief when the fatal cause was finally verified. What’s more, researchers had come up with a test capable of detecting the minutest traces of melamine.
The method was developed by a company in Sweden, located in the small university town of Umeå, around 400 kilometres from the Arctic Circle. Merck SeQuant, part of the Merck Group since 2008, was originally a start-up venture spawned by a university research project in 1997. Since then the company has specialised in methods for separating and detecting biomolecules in complex mixtures. “When the pet food scandal hit the news in 2007, we started a joint project with the US Food and Drug Administration to develop a test for melamine,” recalls Einar Ponten, cofounder and managing director of Merck SeQuant. “At the same time we also collaborated with the Chinese authorities. When the scandal reached a new dimension in autumn 2008, we were all geared up and able to rapidly modify our test for use on milk powder.
In milk powder instead of kitchen units
Yet why was melamine illicitly added to milk powder in the first place? For a start, it is cheaper than milk powder; and secondly, it was previously undetectable, either visually or chemically. Melamine is a constituent of melamine resin, which is used, for example, to surface the chipboard used in kitchen cabinets. When ground to a white powder, it is practically impossible to tell it apart from milk powder by mere sight. On a chemical level, the protein content of milk powder is measured using a simple test for nitrogen. Melamine, however, is two-thirds nitrogen and, as such, ideal for giving the appearance of a higher protein content.
It is quite possible that unscrupulous manufacturers have been adding melamine to milk powder for years, since it is not especially toxic on its own. Indeed, it is only in combination with a second substance, cyanuric acid, that it becomes dangerous. From a chemical point of view, cyanuric acid is very similar to melamine. When combined, the two form insoluble crystals, which can be fatal if they occur in the kidneys. Given that cyanuric acid is formed when melamine decomposes, it may also be assumed that some manufacturers were using low-quality, impure forms of melamine to add to their milk powder. In any event, a reliable method to detect the presence of both substances at the same time is vital. And that’s exactly what the Merck SeQuant test does.