title: Distribution of Animal Drugs among Curd, Whey, and Milk Protein Fractions in Spiked Skim Milk and Whey.
abstract: It is important to understand the partitioning of drugs in processed milk and milk products, when drugs are present in raw milk, in order to estimate the potential consumer exposure. Radioisotopically labeled erythromycin, ivermectin, ketoprofen, oxytetracycline, penicillin G, sulfadimethoxine, and thiabendazole were used to evaluate the distribution of animal drugs among rennet curd, whey, and protein fractions from skim cow milk. Our previous work reported the distribution of these same drugs between skim and fat fractions of milk. Drug distribution between curd and whey was significantly correlated (R2= 0.70) to the drug's lipophilicity (log P), with improved correlation using log D (R2= 0.95). Distribution of drugs was concentration independent over the range tested (20-2000 nM). With the exception of thiabendazole and ivermectin, more drug was associated with whey protein than casein on a nmol/g protein basis (oxytetracycline experiment not performed). These results provide insights into the distribution of animal drug residues, if present in cow milk, among milk fractions, with possible extrapolation to milk products.
authors.affiliation: USDA-ARS, Biosciences Research Laboratory , 1605 Albrecht Boulevard, Fargo, North Dakota 58102-2765, United States.
authors.forename: Nancy W
authors.identifier: http://orcid.org/0000-0003-4080-4372
authors.initials: NW
authors.lastname: Shappell
authors.affiliation: USDA-ARS, Biosciences Research Laboratory , 1605 Albrecht Boulevard, Fargo, North Dakota 58102-2765, United States.
authors.forename: Weilin L
authors.identifier: http://orcid.org/0000-0002-4721-9945
authors.initials: WL
authors.lastname: Shelver
authors.affiliation: USDA-ARS, Biosciences Research Laboratory , 1605 Albrecht Boulevard, Fargo, North Dakota 58102-2765, United States.
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Lupton
authors.affiliation: US-FDA, Center for Food Safety and Applied Nutrition , 5001 Campus Drive, College Park, Maryland 20740, United States.
authors.forename: Wendy
authors.initials: W
authors.lastname: Fanaselle
authors.affiliation: US-FDA, Center for Food Safety and Applied Nutrition , 5001 Campus Drive, College Park, Maryland 20740, United States.
authors.forename: Jane M
authors.initials: JM
authors.lastname: Van Doren
authors.affiliation: USDA-ARS, Biosciences Research Laboratory , 1605 Albrecht Boulevard, Fargo, North Dakota 58102-2765, United States.
authors.forename: Heldur
authors.initials: H
authors.lastname: Hakk
mesh_terms: D000818:Animals; D002417:Cattle; D003257:Consumer Product Safety; D004350:Drug Residues / Q000032:analysis*; D007559:Ivermectin / Q000032:analysis; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000032:analysis*; D013827:Thiabendazole / Q000032:analysis; D019155:Veterinary Drugs / Q000032:analysis*; D000067796:Whey / Q000737:chemistry*
chemical_list: D008894:Milk Proteins; D019155:Veterinary Drugs; D007559:Ivermectin; D013827:Thiabendazole
keywords: NSAID; anthelmintic; antibiotic; curd; distribution; drug residues; partition; protein association; skim milk; whey