Mid-infrared spectroscopy and chemometrics for the authentication of meat products

Mid-infrared (MIR) spectroscopy is used to address certain issues connected with the authentication of beef and ox kidney and liver: is it possible to distinguish muscle from offal tissue; does the condition, cut of meat, or type of offal influence the distinction; can pure minced beef be distinguis hed from that adulterated with offal? Using partial least squares (PLS) and canonical variate analysis, predictive models are developed to identify MI R spectra of beef, kidney, and liver. Using modified SIMCA, the pure beef s pecimens are modeled as a single class; this model identifies spectra of un adulterated beef as such, with an acceptable error rate, while rejecting sp ectra of specimens containing 10-100% w/w kidney or liver. Finally, PLS reg ressions are performed to quantify the amount of added offal. The predictio n errors obtained (+/-4.8 and +/-4.0% w/w, respectively, for the kidney and liver calibrations) are commensurate with the detection limits suggested b y the SIMCA analysis.