How Did Chromatography Resolve the Chinese Milk Scandal?

Food safety is something that most of us take for granted nowadays. We buy food and eat it without a thought that we will become ill. Occasionally though, food scandals can happen in the UK — never mind in the far-flung corners of the globe. Remember the horse meat scandal and the non-organic organic eggs being sold in supermarkets?

There is still an active role for analytical chemistry in not only keeping us safe — but also investigating when things go wrong in the food supply chain. A recent article in the Royal Society of Chemistry journal ‘Education in Chemistry’ discussed one such scandal, and the role chromatography played in putting things right.

Toxic baby milk

The scandal began unfolding in 2008 — when China was playing host to the biggest party in the world as Beijing hosted the summer Olympics. In the north west province of Gansu, babies were falling ill. It is thought that over 300,000 babies were affected with over 54,000 babies hospitalized and six deaths. The problem was eventually found to be milk and formula powders for babies that had been adulterated with melamine.

Melamine has a high nitrogen content which gave the impression that the protein content of the milk was ok. A subsequent investigation was unable to identify exactly when melamine was added to the milk supplies. Melamine can be found naturally in milk products — as a result of farm animals eating plants that have been treated with certain pesticides. But these are always at very low levels.

Kidney stones and failure

The toxic baby powder had melamine at significantly higher levels, and it is thought that it had been added to boost the protein content of the milk powder. Unfortunately, this can lead to kidney stones forming that can block tubes in small kidneys leading to kidney failure. It is not known how many affected babies will suffer kidney problems in later life.

Detecting melamine — chromatography helps

As babies started to fall ill, food analysis labs were trying to find the cause of the problem. One of the initial problems was the fact that melamine is not a normal chemical to test for in milk powders — and there were no standard methods to detect melamine in foodstuffs. And that is where chromatography comes in. As discussed in the article, Identification of an Unknown Constituent in Hemp-Derived Extract Using Reversed-Phase Orthogonal Methodology — chromatography is a powerful technique at finding hidden substances.

During the scandal, several companies developed techniques for analysing foodstuffs for melamine and other potentially toxic additives. Chromatography’s ability to separate compounds based on their affinities for different solid/liquid matrices makes it one of the most powerful of all analytical techniques. With the new methods, food companies were able to assure agencies that their products were now clear of melamine. But consumer confidence is very hard to win back.