Distribution of Chemical Residues among Fat, Skim, Curd, Whey, and Protein Fractions in Fortified, Pasteurized Milk

The distribution of 12 environmental contaminants or metabolites with diverse polarities (2,2',4,4',5-pentabromodiphenyl ether; bisphenol A; estrone; glyphosate; β-hexabromocyclododecane; imidacloprid; 2,3',4,4',5-pentachlorobiphenyl; 3'-methylsulfone 2,2',4,5,5'-pentachlorobiphenyl; 1,2,7,8-tetrachlorodibenzo- p -dioxin; 2-hydroxy-1,3,7,8-tetrachlorodibenzo- p -dioxin; tetrabromobisphenol A; and triclocarban) among skim milk, fat, curd, whey, whey retentate, and whey permeate was characterized. Analysis of these compounds along with 15 drugs previously studied provided a robust linear model predicting the distribution between skim and fat and the chemical's lipophilicity (log P , r 2 = 0.71; log D , r 2 = 0.79). Similarly, distribution between curd and whey was correlated with lipophilicity (log P , r 2 = 0.63; log D , r 2 = 0.73). Phenolic compounds had less predictable distribution patterns based on their lipophilicities. Within the whey fraction, chemicals with greater lipophilicity are associated with whey proteins more than hydrophilic chemicals. The resultant model could help predict the potential distribution of chemical contaminants among milk products in cow milk, if present.