Evaluation of Milkoscan 104 Infrared Milk Analyzer

Abstract

Abstract The Milkoscan 104, a single cell, dual wavelength infrared milk analyzer, was assessed to see if it would meet the newly set AOAC specifications for accuracy and reproducibility required for official sanctioning of the instrument for milk component analysis. This assessment was carried out using herd, individual cow, commercial, and composite random milks, and produced mean differences and standard deviations of difference of <0.02% and ±0.02% for reproducibility and <0.05% and ±0.06% for accuracy. Results outside these values were encountered in the individual cow milks, for which the instrument was not specifically calibrated. The average molecular weight of the milkfat was an important variable because 2 anomalous milks were present in the calibration milks, thus restricting the overall accuracy obtainable. Linear regression analysis of chemical vs instrumental results showed good linearity and provided standard errors of the estimate of the same magnitude as the standard deviation of the differences. A separate assessment of the instrument for within- and between-day variation showed no practical significant differences. Based on the overall results, the Milkoscan 104 was judged to be capable of meeting the AOAC specifications set for fat, protein, and lactose analysis.