Near-infrared spectroscopy for biomonitoring: influence of somatic cell count on cow's milk composition analysis

The influence of milk with high somatic cell count on the accuracy of near- infrared spectroscopic determination of fat, protein and lactose content of non-homogenized milk was investigated. Transmittance spectra of 258 milk s amples were obtained by the NIRSystem 6500 spectrophotometer in the 700-110 0 nm region. The best accuracy for fat, protein and lactose content determi nation was found for calibration equations, derived from samples with low s omatic cell count (SCC). The standard error of prediction increased and the correlation coefficient decreased significantly, both when equations, deri ved from samples with low SCC milk were used to predict the content of the examined components in samples with high SCC, and when equations, obtained for samples with high SCC were used to predict the content of the component s in samples with low SCC. Therefore, milk samples with high SCC in a data set used for calibration or prediction highly influenced the accuracy of fa t, protein and lactose determination. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.