title: Identification of goat milk powder by manufacturer using multiple chemical parameters.
abstract: Concentrations of multiple elements and ratios of stable isotopes of carbon and nitrogen were measured and combined to create a chemical fingerprint of production batches of goat whole milk powder (WMP) produced by different manufacturers. Our objectives were to determine whether or not differences exist in the chemical fingerprint among samples of goat WMP produced at different sites, and assess temporal changes in the chemical fingerprint in product manufactured at one site. In total, 58 samples of goat WMP were analyzed by inductively coupled plasma-mass spectrometry as well as isotope ratio mass spectrometry and a suite of 13 elements (Li, Na, Mg, K, Ca, Mn, Cu, Zn, Rb, Sr, Mo, Cs, and Ba), δ(13)C, and δ(15)N selected to create the chemical fingerprint. Differences in the chemical fingerprint of samples between sites and over time were assessed using principal components analysis and canonical analysis of principal coordinates. Differences in the chemical fingerprints of samples between production sites provided a classification success rate (leave-one-out classification) of 98.1%, providing a basis for using the approach to test the authenticity of product manufactured at a site. Within one site, the chemical fingerprint of samples produced at the beginning of the production season differed from those produced in the middle and late season, driven predominantly by lower concentrations of Na, Mg, K, Mn, and Rb, and higher concentrations of Ba and Cu. This observed temporal variability highlights the importance of obtaining samples from throughout the season to ensure a representative chemical fingerprint is obtained for goat WMP from a single manufacturing site. The reconstitution and spray drying of samples from one manufacturer by the other manufacturer enabled the relative influence of the manufacturing process on the chemical fingerprint to be examined. It was found that such reprocessing altered the chemical fingerprint, although the degree of alteration varied among samples and individual elements. The findings of this study support the use of trace elements and stable isotope ratios to test the authenticity of goat WMP, which can likely be applied to other dairy goat products. This approach could be used test to the factory of origin (and potentially batch of origin) of products in the supply chain, thus providing the ability to audit the supply chain and monitor for fraudulent activity.
authors.affiliation: Oritain Global Ltd., Private Bag 50034, Mosgiel, Otago 9053 New Zealand. Electronic address: rmcleod@oritain.com.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: McLeod
authors.affiliation: Dairy Goat Co-operative, 18 Gallagher Drive, Hamilton, 3206 New Zealand.
authors.forename: Colin G
authors.initials: CG
authors.lastname: Prosser
authors.affiliation: Oritain Global Ltd., Private Bag 50034, Mosgiel, Otago 9053 New Zealand.
authors.forename: Joshua W
authors.initials: JW
authors.lastname: Wakefield
mesh_terms: D000818:Animals; D005506:Food Contamination / Q000032:analysis; D005511:Food Handling; D057141:Food, Preserved / Q000032:analysis*; D006041:Goats; D007554:Isotopes / Q000032:analysis; D013058:Mass Spectrometry / Q000379:methods; D008892:Milk / Q000737:chemistry*; D009426:Netherlands; D009520:New Zealand; D025341:Principal Component Analysis; D012621:Seasons; D014131:Trace Elements / Q000032:analysis
chemical_list: D007554:Isotopes; D014131:Trace Elements
keywords: dairy goat; origin; stable isotope ratios; trace elements; whole milk powder