Chemical composition of raw milk and heavy metals behavior during processing of milk products.

Abstract

Abstract: Whole buffalo's and cow's milk as well as dairy products manufactured from them were analyzed for chemical composition and metal contents. Buffalo's milk showed higher levels of fat (4.9%), total protein (3.6%), total solids (13.4%) and ash (0.76%) than cow's milk (3.2, 3.2, 12.1 and 0.65%, respectively). Also, higher levels were detected in pasteurized and sterilized buffalo's milk. However, lactose content in cow's milk was higher (5.0%) than buffalo's milk (4.8%). Most of gross composition was found at higher levels in cream, butter, samna (ghee) and yoghurt from buffalo's milk as compared with cow's milk. Metals, i.e. iron (Fe), copper (Cu), manganese (Mn) and zinc (Zn) were detected in buffalo's milk at concentrations of 0.88, 0.201, 0.072 and 4.35 mg/kg milk and were higher than in cow's milk (0.572, 0.131, 0.047 and 2.828 mg/kg, respectively). Also cow’s milk contained chromium (Cr), nickel (Ni), cobalt (Co) and tin (Sn), at lower levels. Harmful metals such as lead (Pb) and cadmium (Cd) were detected in the collected samples at low levels. Metals contents were concentrated in dairy products manufactured from buffalo's milk at higher levels as comparing to cow's milk.