The melamine problem in China first became evident in spring 2008 with the increase in urinary tract stone formation in infants. More than 294,000 children have reportedly been affected by adulterated formula, with over 50,000 hospitalized and at least 6 deaths. The melamine crises in China 2009 with 22 dairy companies were involved, has pointed out a serious deficiency in the current food control system, which specifically targets a set of selected known compounds. With the targeted approach the presence of melamine in milk products could go undetected for a long time.

With our NMR-based targeted and non-targeted feasibility study consisting of 9 authentic Chinese infant formulas that have been bought in Beijing in September 2008 and 13 German infant formulas that have been bought in Baden Wurttemberg in December 2008 we were able to distinguish between melamine-contaminated and melamine-free infant formulas. Additionally we could provide quantitative information to the samples. It became quickly evident, that even by a simple visual inspection of the NMR spectra, the Chinese San-Lu sample showed differences.

Besides the direct detection of melamine using DSMO as solvent, the frauded sample could also be detected in aqueous solution due to the addition of sucrose. Sucrose was obviously added to increase the sugar content of the diluted milk which had to be done to compensate the increased nitrogen content due to the melamine addition. A simple test is usually used to check the ratio of nitrogen vs. sugar content. This test fails if both contents are adjusted as in the sample found. Sucrose was identified by comparison to our spectra base of pure compounds.

Also one German infant formula sample deviated from all other samples. The signal for lactose was missing, showing that with the same measurement also different types of milk can be distinguished. This shows, that the NMR method can also allow controlling recipes and labelling claims. In conclusion we can say that our NMR based screening method, with the option of a non-targeted experiment along with the structural information inside the spectra, brings a lot of advantages compared to conventional techniques.