Determination of nutritional and toxic elements in pasteurized bovine milk from Vale do Paraiba region (Brazil)

Throughout the year of 2004, 54 samples (1 L each) were collected from commercial sources in the Vale do Paraíba region (eastern portion of São Paulo State, Brazil). The concentrations of (Ca, Cr, Cu, Fe, Mg, Mn, Ni, Se, Zn, Cd and Pb) in these samples were analyzed by two atomic-absorption spectroscopy (AAS) methods. Ca, Cu, Fe, Mg and Zn were determined by flame atomic-absorption spectroscopy (FAAS) and (Cd, Cr, Mn, Ni, Pb and Se) were determined by electrothermal atomic-absorption spectroscopy (ETAAS). Tests to determine and quantify essential, nonessential and toxic elements present in bovine milk are rare in Brazil, especially so for Vale do Paraiba region. Tests were performed on standard NIST-certified milk-powder to validate the reliability of subsequently collected analytical data. Ca presented a lower recovery value (85.3%). The finding for Ca macro-nutrient was found to be below recommended international standards (1300 mg/L) for all samples possibly due to milk heterogeneity and losses in the pasteurization process. Significant results for Pb were found in all milk samples with average values at 0.230 mg/L from a minimum of 0.062 mg/L and maximum of 0.476 mg/L.