The certification of a PH05-026-0048 potato tuber powder for its identity (ERM®-BF435b) and the certification of a blank material (ERM®-BF435a)

This report describes the production of two Certified Reference Materials (CRMs) ERM-BF435a and b. ERM-BF435a was certified to contain less than the limit of the detection (LOD) of the event-specific PH05-026-0048 polymerase chain reaction (PCR) method applied. ERM-BF435b was certified for its genetic identity with respect to the potato event PH05-026-0048. These dried potato powder materials were produced following ISO Guide 34:2009. Potato (Solanum tuberosum) tubers from the genetically modified (GM) potato event PH05-026-0048 were cut into small pieces, dried and ground to obtain the GM potato powder for ERM-BF435b. Potato tubers from a non-GM potato variety were treated in the same way to obtain the non-GM potato powder for ERM-BF435a. The purity of the raw materials used for producing ERM-BF435a and b has been established on the individual potato tubers used for processing. Various PCR screening methods were applied on each non-GM potato tuber to confirm that they are non-modified potato tubers. The GM potato tubers were tested applying an event-specific PH05-026- 0048 PCR method. After processing of the two powders and additionally after filling of the CRMs, the non-GM and GM materials were tested with an event-specific PH05-026-0048 PCR method confirming the presence/absence of the event PH05-026-0048. All measurements were carried out by experienced laboratories holding an ISO/IEC 17025:2005 accreditation for GM measurements. The event-specific PH05-026-0048 detection carried out on the powders was, however, not included in the scope of accreditation. An in-house validated presence/absence testing method for the event PH05-026-0048 is made available in this certification report (Annex A), but no validated quantitative PCR method is currently available. Stability during dispatch and storage were therefore assessed on potato powders processed in a similar way, for which a validated quantitative PCR method was available. The assessments were carried out in accordance with ISO Guide 35:2006. The uncertainties related to the certification process were estimated as far as possible in accordance with ISO/IEC Guide 98-3, Guide to the Expression of Uncertainty in Measurement (GUM:1995), ISO, 2008. The materials are intended to be used as negative and positive control materials for the GM event PH05-026-0048. The CRMs are available in glass vials containing at least 1 g of dried potato tuber powder closed under argon atmosphere. The recommended minimum amount of sample to be used is 200 mg. The CRMs were accepted as European Reference Material (ERM®) after peer evaluation by the partners of the European Reference Materials consortium.