Behaviour of pesticides lindane and methyl parathion during manufacture, ripening and storage of feta cheese

The behaviour of the pesticides lindane and methyl parathion during the manufacture, ripening and storage of feta cheese was investigated. Pasteurization of milk at 63–65°C for 30 min did not affect the concentrations of either pesticide. Lindane and methyl parathion at concentrations of 0.10 mg/kg and 16.66 mg/kg of milk, respectively, did not affect the activity of the starter culture. The concentration of lindane in the cheese and in whey/brine did not change significantly during ripening (up to 240 days). The concentration of methyl parathion in the cheese increased progressively up to 120 days of ageing, but decreased significantly (P < 0.05) from 120 up to 240 days. Methyl parathion might be bound to casein, in particular to the seryl and phosphoseryl groups of casein. Changes of brine to decontaminate the feta cheese from methyl parathion and lindane residues did not affect their concentrations in the cheese.