Trace metals in raw cows’ milk and assessment of transfer to Comté 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 μg/g; Cu: 0.28–1.71 μg/g; Zn: 20.62–30.96 μg/g), concentrations in the corresponding cheese were significantly higher (Cd: 0.68–11.37 ng/g; Pb: 0.020–0.925 μg/g; Cu: 5.35–21.34 μg/g; Zn: 33.66–63.41 μg/g). The retention factor Rt 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, Comté cheese may constitute a useful source of Cu and Zn in human diet.

► Transfer of essential (Cu, Zn) and non essential (Pb, Cd) elements from raw milk to Comté cheese were studied.
► Comté is a Protected Designation of Origin pressed cooked cheese made with unpasteurised milk.
► Cu, Zn, Pb and Cd concentrations were low in milk and significantly higher in Comté cheese.
► Pb and Cd concentrations in Comté cheese remain largely below those dangerous for consumers.
► Comté cheese may be an useful source of Cu and Zn in human diet.