Potential of Raman Spectroscopy and Imaging Methods for Rapid and Routine Screening of the Presence of Melamine in Animal Feed and Foods

Potential of Raman spectroscopy and imaging methods for rapid and routine screening of the presence of melamine in animal feed and foods, was studied. Melamine, dry food/feed materials and disposable glass tubes were obtained. At least five mixtures were prepared for each food/feed material type by mixing melamine into the dry material to obtain contaminant concentrations in the range of 0.2, 0.5, 1.0, 3.0, and 6.0%. A mortar and pestle were used to obtain homogeneous mixtures. The FT-Raman spectra were acquired on a FT-Raman module using an InGaAs detector and XT-KBr beamsplitter. The samples in the glass tubes were illuminated using the Nd:YAG excitation laser operating at 1064 nm. Raman scattered light was accumulated using a 180° reflective mode with 0.5 W of laser power and 2.56 scans at 8 cm -1 resolution. FTIR results show that melamine and wheat flour have unique Raman bands that increase or decrease in intensity in accordance with the relative amount of melamine.