Heavy metals in cow's milk and cheese produced in areas irrigated with waste water in Puebla, Mexico.

The aim of this work was to determine Ni, Cr, Cu, Zn, Pb, and As levels in raw milk and Oaxaca and ranchero type cheeses, produced in areas irrigated with waste water from Puebla in Mexico. Milk results showed a mean Pb level of 0.03 mg kg-1, which is above the maximum limit as set by Codex Alimentarius and the European Commission standards. For As a mean value of 0.12 mg kg-1 in milk was obtained. Mean As and Pb levels in milk were below the Mexican standard. Milk whey and ranchero cheese had mean Pb levels of 0.07 and 0.11 mg kg-1, respectively. As was higher in Oaxaca and ranchero cheese at 0.17 and 0.16 mg kg-1, respectively. It was concluded that cheeses made from cow's milk from areas irrigated with waste water are contaminated with Pb and As, which may represent a health risk.