Development of milk powder reference materials certified for aflatoxin M1 content (Part I)

The development of 3 full-cream milk powder reference materials, certified for their aflatoxin M1 content, is described. The materials were prepared and certified within the Reference Material Programme of the Community Bureau of Reference (BCR). The 3 reference materials, RMs 282, 284, and 285, contain aflatoxin M1 at concentrations of less than 0.05, 0.31 +/- 0.06, and 0.76 +/- 0.05 micrograms/kg, respectively. The preparation, testing for homogeneity, stability of the reference materials, and the certification exercise, which was preceded by 2 intercomparisons of methods, are discussed. Particular emphasis was placed on the independence of the measurements in the certification exercise and the control of errors associated with extraction efficiency and the aflatoxin M1 calibrant. Finally, some guidance is given on avoiding the principal sources of errors in the determination of aflatoxin M1. Details concerning the supply of the reference materials will be provided by BCR on request.