Monitoring of some toxic heavy metals in raw milk and effect of heating on metal load of milk

Heavy metals such as lead (Pb), cadmium (Cd), and aluminum (Al) characterized by their bioaccumulation and biomagnification in the animal and human bodies causing multiple organ damage. The present study aimed at estimation of the residual content of Pb, Cd, and Al in the retailed cow’s and buffaloes’ milk collected from urban and rural areas in Sharkia Governorate, Egypt. In addition, the effects of the heat treatment of the milk in different cooking wares (made from aluminum, glass, and stainless steel) were further examined. The public health significance of the studied metals was discussed. The obtained results revealed detection of the tested metals in all examined samples at variable concentrations. In general cow’s milk had higher contents of Pb, Cd, and Al compared with the milk of buffaloes. Moreover, milk sampled from rural areas had significantly higher metal load compared with that sampled from urban areas. Heating of the milk in aluminum-made cooking wares significantly increased Al residues in the heat-treated milk with slight increase in the load of Pb, and Cd. While heating of the milk in cooking wares made from glass had slight reduction in the metal load of the milk. Therefore, it is highly recommended to use glass wares for heating of the milk instead of aluminum wares to avoid leaching of toxic metals to the heated milk.