Vanilla is a high value flavouring used in ice cream, desserts and confectionery, and mainly grown in Madagascar. Synthetic vanillin and biovanillin (produced by fermentation) are cheaper. By using SIRA (stable isotope ratio analysis) to look at the δ13C, it is possible to distinguish between the three types of vanilla flavouring. The method was tested on market samples of yoghurt and ic cream. Also FTIR (Fourier Transform Infrared) spectoscopy with chemometric analysis was calibrated with authentic samples of black pepper so that it was possible to detect the adulteration of ground black pepper with black pepper husk and defatted spent material. The research was undertaken as a Ph.D registered at the Technical University of Denmark, but carried out at the Danish National Food Institute and IGFS - Queens University Belfast.