Certification of reference materials of maize seed powder containing genetically modified MON 810 maize : certified reference materials ERM-BF413k (ERM-BF413ak, ERM-BF413ck, ERM-BF413ek, ERM-BF413gk)

This report describes the processing and certification of four maize seed powder Certified Reference Materials (CRMs) containing different mass fractions of genetically modified (GM) MON 810 maize (ERM-BF413ak, ck, ek, gk). The materials were processed and certified in 2007/2008 by the European Commission, Joint Research Centre, Institute for Reference Materials and Measurements (IRMM, Geel, Belgium), according to the principles of ISO Guide 34. The four CRMs belonging to the ERM-BF413k series replace the earlier produced series ERM-BF413 which is exhausted. The four CRMs have been accepted as European Reference Material (ERM) after peer evaluation by the partners of the European Reference Materials consortium. Hybrid seeds of GM MON 810 maize and of a comparable non-GM maize variety were dried and ground to GM and non-GM base powders. A non-GM pure material and three gravimetric mixtures of non-GM and GM maize powder were prepared by dry-mixing. The certified values of these CRMs were calculated from the gravimetric preparations, taking into account the GM purity of the base materials and their water mass fraction. The certified values were confirmed by event-specific real-time PCR as independent verification method (measurements within the scope of accreditation to ISO/IEC 17025). European Commission Recommendation (EC) No 787/2004 advises to express the content of genetically modified food and feed as the percentage of genetically modified DNA copy numbers in relation to target taxon-specific DNA copy numbers calculated in terms of haploid genomes, the so-called GM DNA copy number ratio. An interlaboratory comparison was, therefore, conducted in 2008 to certify one of the CRMs, ERM-BF413ek, additionally for the GM DNA copy number ratio. The CRMs are intended for the quality control or calibration of methods for the quantification of MON 810 maize in food and feed. The CRMs are available in glass vials containing 1 g of dried maize powder closed under argon atmosphere. The minimum sample intake per analysis is 100 mg.