Trace Metal and Protein Concentrations in California Market Milks

Abstract

Market milk samples (225) were collected in three major milk marketing areas in California. Samples represented four products; regular, extra-rich, non-fat, and low-fat milk. Concentrations of cadmium, copper, lead, zinc, and protein were measured in all samples. The concentration of selenium was measured in 103 of the samples. Mean contrations in all samples examined were: cadmium 5.0; copper, 41.0; lead, 60.3; and selenium, 24.4 μg/kg. No significant differences between market or product means were found for these four metals. Mean product concentrations for protein and zinc were: regular milk, 3.29% protein and 3.61 mg/kg zinc; extra-rich milk, 3.33% and 3.70 mg/kg; non-fat milk, 3.61% and 3.98 mg/kg; and low-fat milk, 3.82% and 4.18 mg/kg. Low-fat and nonfat milks had significantly (a = .05) greater concentrations of protein and zinc than did regular and extra-rich milks.