EFFECTS OF PROCESSING ON THE CONCENTRATION OF LEAD IN MANCHEGO-TYPE CHEESE

Variations in lead content were determined throughout the process of m anufacturing cheese, using graphite furnace atomic absorption spectrop hotometry and taking samples of natural, pasteurized milk, with additi ons of rennet, curd whey, pressed curd, pressing whey and cheese. The mean content of lead in cheese was 211 mug/kg on dry weight. Statistic ally significant differences (p < 0.001) were found in the lead levels in the products from cheese-making, expressed both on wet weight and dry weight. Certain differences were observed in the groups formed on using a Scheffe homogeneity test (p < 0.05) depending on whether the l ead content was expressed on wet weight or on dry weight. Slight rises in the lead content based on dry weight were shown to be mainly due t o the retention of lead by curd and, secondly, by possible contaminati on occurring during the process.