Certification of the crude Protein, Fat, Lactose and Ash Content of whole Milk Powder and the crude Protein and Fat Content of Skim Milk Powder, BCR-380R & BCR-685

Abstract

This report describes the preparation of two milk powder reference materials and the measurement exercises that led to the certification of the content (mass fraction) of the crude protein (Kjeldahl-N x 6.38), fat, lactose and ash in whole milk powder (BCR-380R) and crude protein (Kjeldahl-N x 6.38) and fat in skim milk powder (BCR-685). The certified values are presented in Tables I and II. The results of the certification exercise, which involved material characterisation by a collaborative study involving several experienced European laboratories, are presented and discussed. Uncertainties were calculated in compliance with the Guide to the Expression of Uncertainty in Measurement (GUM) [1]. The stated uncertainties include contributions regarding the results of the characterisation measurements and uncertainties due to potential inhomogeneity and potential instability of the materials. The values carried by the certified reference materials are traceable to methods standardised by the International Dairy Federation (IDF), the International Organization for Standardization (ISO) and AOAC International. Table I: Certified mass fraction of main components in whole milk powder – BCR-380R Mass fraction in g/100 g 1) Parameters Certified value Uncertainty 3) Relative uncertainty 3) in % No. of accepted sets of results Crude protein (Kjeldahl-N x 6.38) 28.66 0.28 1.0 6 Fat 26.95 0.16 0.6 6 Lactose (anhydrous) 37.1 1.0 2.7 11 Ash 6.00 0.13 2.1 8 1) Results corrected for dry mass. 2) Unweighted mean value of the means of accepted sets of results, each set being obtained in a different laboratory applying relevant methods of analysis standardised by IDF/ISO and AOAC The certified values are traceable to the SI. 3) Expanded uncertainty with a coverage factor of k = 2, according to the Guide to the Expression of Uncertainty in Measurement, corresponding to a level of confidence of about 95 %. Table II: Certified mass fraction of main components in skim milk powder BCR-685 Mass fraction in g/100 g 1) Parameters Certified value Uncertainty 3) Relative uncertainty 3) in % No. of accepted sets of results Crude protein (Kjeldahl-N x 6.38) 38.2 0.4 1.0 7 Fat 0.96 0.12 12.6 6 1) Results corrected for dry mass. 2) Unweighted mean value of the means of accepted sets of results, each set being obtained in a different laboratory applying relevant methods of analysis standardised by IDF/ISO and AOAC The certified values are traceable to the SI. 3) Expanded uncertainty with a coverage factor of k = 2, according to the Guide to the Expression of Uncertainty in Measurement, corresponding to a level of confidence of about 95 %. The mission of the JRC is to provide customer-driven scientific and technical support for the conception, development, implementation and monitoring of EU policies. As a service of the European Commission, the JRC functions as a reference centre of science and technology for the Union. Close to the policy-making process, it serves the common interest of the Member States, while being independent of special interests, whether private or national. LA -N A -2315-EN -C