Detection of buffalo milk adulteration with cow milk by capillary electrophoresis analysis

Abstract

The addition of cow milk during the production of buffalo mozzarella is a common fraud in dairy industries because of the lower price and greater availability of cow milk throughout the year. The aim of this study was to develop a new, rapid, and robust capillary electrophoresis method for detecting and quantifying cow milk in buffalo milk by exploiting cow α-lactalbumin as a marker of adulteration. In particular, a linear calibration curve was generated, using a training set of calibrators consisting of 7 series of 17 buffalo/bovine whey mixtures, obtained after casein precipitation, with increasing percentages of cow whey. The capillary electrophoresis method showed high linearity (R² = 0.968), repeatability [relative standard deviation (RSD) = 2.11, 3.02, 4.38, and 1.18%, respectively for 5, 10, 20, and 50% of buffalo/bovine whey mixtures], and intermediate precision (RSD = 2.18, 2.49, 5.09, and 3.19%, respectively, for 5, 10, 20, and 50% buffalo/bovine whey mixtures). Moreover, the minimum amount of detectable fraudulent cow milk was 1%, and the limit of quantification was 3.1%.

Keywords: buffalo; capillary electrophoresis; cow; milk adulteration.