Trace metals in raw cows' milk and assessment of transfer to Comte cheese

As part of a program to assess the transfer of metals from soil to dairy products, the transfer of metal trace elements to milk and cheese was studied. Concentrations of non-essential (Cd and Pb) and essential elements (Cu and Zn) were determined by atomic absorption spectrometry in 61 samples of raw milk and 21 of the corresponding cheese. While metal concentrations (dry weight) in raw milk were very low (Cd: 0.34-1.01 ng/g; Pb: 0.009-0.126 mu g/g; Cu: 0.28-1.71 mu g; Zn: 20.62-30.96 mu g/g), concentrations in the corresponding cheese were significantly higher (Cd: 0.68-11.37 ng/g; Pb: 0.020-0.925 mu g/g; Cu: 5.35-21.34 mu g/g; Zn: 33.66-63.41 mu g/g). The retention factor R-t suggests a concentration effect during the cheese making process, especially in the case of Cu, due to the use of large copper vats. Concentrations of non-essential elements (Cd and Pb) in cheese largely remained below those considered as dangerous for consumers. Finally, Comte cheese may constitute a useful source of Cu and Zn in human diet. (C) 2010 Elsevier Ltd. All rights reserved.