INORGANIC COMPOSITION AND RAMAN SPECTROSCOPY AS NEW METHODS FOR THE IDENTIFICATION OF ANIMAL MEALS RESIDUED IN FEED

Our study is aimed at evaluating the possibility of using inorganic composition and Raman spectroscopy as possible alternative methods of analysis for the individuation and characterization of Processed Animal Proteins (PAPs) in animal feeds. The official analysis method approved by European Commission is based on optical microscopy [1], and on Real Time PCR. However, both methods present some drawbacks, (e.g. high staff specialization). Particularly, microscopy does not permit the identification of animal species present in feed. PCR methods are specific and sensitive in nature [2], but they are not able to distinguish between allowed and not allowed ingredients (e.g. Milk versus PAP). Many other techniques, as infrared microscopy, immunoassay methods, chromatographic and mass-spectrometry, were just evaluated as possible alternative methods. All these methods show advantages and limitations [3]. Four types of pure PAPs, namely bovine, swine, poultry and fish-based PAPs, have been analyzed using an inductively coupled plasma optical emission spectrometer (ICP-OES) and a FT-RAMAN spectrometer. All the procedure steps (samples pretreatment and analysis) and all the parameters and conditions were considered and optimized. The application of multivariate chemometric techniques to the experimental results allowed us to determine the identification capability of the two techniques, to identify correlations among the variables and to reveal similarities and differences among the different species.