Cadmium variations in Manchego cheese during traditional cheese-making and ripening processes

Variations in cadmium content were determined throughout cheese manufacturing and ripening processes by applying graphite furnace atomic absorption spectrophotometry to samples of natural pasteurized milk, rennet, curd whey, pressed curd, pressing whey and cheese. The total mean cadmium contents were 4.79 +/- 2.4 and 4.67 +/- 2.1 microgram/kg fresh weight for newly-made and mature cheeses respectively. ANOVA revealed statistically significant differences (p < 0.001) in cadmium levels (fresh weight) and these differences were due to the influence of moisture content during cheese manufacture, since no statistically significant differences (p > 0.05) were found for dry weight. Nevertheless, cadmium levels based on dry weight increased during pasteurization and more noticeably on ferment addition. ANOVA performed during the ripening process revealed significant differences between portions and ripening times for both fresh and dry weights. By Tukey's test (p < 0.05) for portions, two homogeneous groups were established, one corresponding to the outer portion with a greater cadmium content and the other comprising the middle and inner portions. The contribution of cadmium to Spanish mean intake is between 0.098 and 0.147 micrograms/week for new cheese and between 0.168 and 0.245 micrograms/week for mature cheese.