Guidelines for sample preparation 
                       procedures in GMO analysis 
                                                         Prepared by the ENGL ad hoc 
                                                         working group on “sample 
                                                         preparation procedures” 
                                                          2014 
                                                                                     Report EUR 27021 EN
                      
                      
                      
                      
                      
                                 
                     European Commission 
                     Joint Research Centre 
                     Institute for Health and Consumer Protection 
                      
                     Contact information 
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                     This publication is a Technical Report by the Joint Research Centre, the European Commission’s in-house science service.  
                     It aims to provide evidence-based scientific support to the European policy-making process. The scientific output expressed does 
                     not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of 
                     the Commission is responsible for the use which might be made of this publication. 
                      
                     All images © European Union 2014 
                      
                     JRC94042 
                      
                     EUR 27021 EN 
                      
                     ISBN 978-92-79-44704-4 (PDF) 
                     ISBN 978-92-79-44705-1 (print) 
                      
                     ISSN 1831-9424 (online) 
                     ISSN 1018-5593 (print) 
                      
                     doi:10.2788/738570 
                      
                     Luxembourg: Publications Office of the European Union, 2014 
                      
                     © European Union, 2014 
                      
                     Reproduction is authorised provided the source is acknowledged. 
                      
                      
                      
                      
                      
                     Abstract 
                      
                     This document aims at providing guidelines for a correct sample preparation in GMO analysis on food, feed, seed, plants and 
                     propagating material samples. It has been developed by the European Network of GMO Laboratories (ENGL), specifically by the 
                     ENGL working group “sample preparation procedures” upon a mandate of the ENGL steering committee. The structure of the 
                     document is based on that of an existing ISO standard (ISO 6498:2012), dealing with sample preparation for feed; starting from 
                     this, the procedures were adapted to the needs of GMO detection and the scope concerning matrices was widen to food, feed 
                     and seeds.  
                      
                     These guidelines cover the key steps of the sample preparation, i.e. the size of the laboratory sample, the mass reduction 
                     techniques as well as techniques for comminution and mixing; considerations about the test portion are included and some 
                     performance tests to be applied at different steps of the process are provided. 
                      
                     While sample preparation, falling after sampling and before analytical testing for GMOs, has suffered from a lack of guidance
                     and harmonization, this document provides detailed and practical hints on this important step, thus contributing to foster testing 
                     harmonisation. 
                      
                        Executive summary 
                         
                        This  document  has  been  developed  by  the  Members  of  the  working  group  ‘sample  preparation 
                        procedures’ based on a mandate of the ENGL steering committee that is detailed in the introduction. 
                        The general structure of the document is based on that of an existing ISO standard (ISO 6498:2012) 
                        handling specifically about sample preparation for feed. Most of the definitions are taken from this 
                        standard.  The  procedures  were  however  adapted  for  GMO  detection  and  the  scope  concerning 
                        matrices is much wider (food, feed and seeds). This has an impact for instance on mass reduction 
                        processes because risk of contamination is  of more  concern  in  GMO  detection.  There  is  a  brief 
                        reminder of the theory of sampling. Within the procedure the most important points are: the size of the 
                        laboratory  sample, the mass reduction techniques as well as techniques for comminution and for 
                        mixing and finally considerations about the test portion. Some performance tests to be applied at 
                        different steps of the process are provided. As a conclusion it is assessed in how far the expectations 
                        of the mandate were addressed, gaps were identified and proposals are made for the future. 
                         
                         
                         
                         
                         
                         
                         
                         
                         
                         
                         
                         
                                                                                                                                                                   
                         
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        Content                        
         
        Executive summary .................................................................................................................................. i 
        Content .....................................................................................................................................................ii 
        Introduction ............................................................................................................................................. 1 
        1 Scope .................................................................................................................................................... 2 
        2 Principle ................................................................................................................................................ 2 
        3 Definitions ............................................................................................................................................ 2 
        4 General considerations related to the theory of sampling .................................................................. 4 
        5 Equipment ............................................................................................................................................ 8 
        6 Environment and rooms ..................................................................................................................... 10 
        7 Safety precautions .............................................................................................................................. 10 
        8 Procedure ........................................................................................................................................... 11 
        9 Performance tests (quality control) ................................................................................................... 22 
        10 Identified gaps and conclusions ....................................................................................................... 24 
        11 Bibliographic references ................................................................................................................... 26 
        Annex I ................................................................................................................................................... 29 
        Annex II .................................................................................................................................................. 30 
        Annex III ................................................................................................................................................. 31 
        Annex IV ................................................................................................................................................ 32 
        Annex V.................................................................................................................................................. 33 
        Annex VI ................................................................................................................................................ 35 
        Annex VII ............................................................................................................................................... 36 
         
         
         
         
         
         
         
         
         
         
         
         
         
         
         
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