1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58chain reaction (PCR) for the detection of food-borne pathogens Requirements for amplification and d
2、etection for qualitative methods The European Standard EN ISO 20838:2006 has the status of a British StandardICS 07.100.30Microbiology of food and animal feeding stuffs Polymerase BRITISH STANDARDBS EN ISO 20838:2006BS EN ISO 20838:2006This British Standard was published under the authority of the S
3、tandards Policy and Strategy Committee on 28 April 2006 BSI 2006ISBN 0 580 48239 1The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or
4、by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immun
5、ity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, the EN ISO title page, the EN ISO foreword page, the ISO title page, pages ii to vi, pages 1 to 7 and a back cover.The BSI copyright notice displayed in this document indicates when the document
6、was last issued.Amendments issued since publicationAmd. No. Date CommentsA list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesenquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related interna
7、tional and European developments and promulgate them in the UK.National forewordThis British Standard is the official English language version of EN ISO 20838:2006. It is identical with ISO 20838:2006.The UK participation in its preparation was entrusted to Technical Committee AW/9, Microbiology, wh
8、ich has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 20838April 2006ICS 07.100.30English VersionMicrobiology of food and animal feeding stuffs - Polymerasechain react
9、ion (PCR) for the detection of food-borne pathogens -Requirements for amplification and detection for qualitativemethods (ISO 20838:2006)Microbiologie des aliments - Raction de polymrisation enchane (PCR) pour la dtection des micro-organismespathognes dans les aliments - Exigences relatives lamplifi
10、cation et la dtection pour les mthodesqualitatives (ISO 20838:2006)Mikrobiologie von Lebensmitteln und Futtermitteln -Polymerase-Kettenreaktion (PCR) zum Nachweis vonpathogenen Mikroorganismen in Lebensmitteln -Anforderungen an Amplifikation und Nachweis beiqualitativen Verfahren (ISO 20838:2006)Thi
11、s European Standard was approved by CEN on 13 April 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
12、 concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its o
13、wn language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembour
14、g, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of e
15、xploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 20838:2006: EForeword This document (EN ISO 20838:2006) has been prepared by Technical Committee CEN/TC 275 “Food analysis - Horizontal methods“, the secretariat of which is held by DIN, in collaborat
16、ion with Technical Committee ISO/TC 34 “Agricultural food products“. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2006, and conflicting national standards shall be withdrawn at the late
17、st by October 2006. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Irelan
18、d, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN ISO 20838:2006Reference numberISO 20838:2006(E)INTERNATIONAL STANDARD ISO20838First edition2006-04-15Microbiology of food and animal f
19、eeding stuffs Polymerase chain reaction (PCR) for the detection of food-borne pathogens Requirements for amplification and detection for qualitative methods Microbiologie des aliments Raction de polymrisation en chane (PCR) pour la dtection des micro-organismes pathognes dans les aliments Exigences
20、relatives lamplification et la dtection pour les mthodes qualitatives EN ISO 20838:2006ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Principle. 1 5 Reagents 2 6 Apparatus and equipment . 3 7 Procedure 4 8 Interpretation. 6 9 Perfor
21、mance 6 10 Test report . 6 Bibliography . 7 EN ISO 20838:2006iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical co
22、mmittees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with th
23、e International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft Internati
24、onal Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. ISO 20838 was prepared by the European Committee for Standardization (CEN) Technical Com
25、mittee CEN/TC 275, Food analysis Horizontal methods, in collaboration with Technical Committee ISO/TC 34, Food products, Subcommittee SC 9, Microbiology, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement). EN ISO 20838:2006vIntroduction The amplification
26、 and detection of target nucleic acid sequences is performed to determine whether certain nucleic acid sequences are present or not in the test portion. This determination is relative to appropriate controls and within the detection limits of the analytical method used and test portion analysed. Thi
27、s International Standard describes the procedure used to detect food-borne microorganisms, including pathogens, by analysing nucleic acids extracted from foodstuffs, feed and environmental samples, or from cultures or cell suspensions prepared from the foodstuff. Appropriate procedures for sample pr
28、eparation, culturing of microorganisms and extraction of nucleic acids are described in ISO 20837. The main focus of this International Standard is on PCR-based amplification methods. However, because of the rapid rate of technological change in this area, other amplification technologies and detect
29、ion methods may be considered. This International Standard is related to a series of standards and a Technical Specification under the general title Microbiology of food and animal feeding stuffs Polymerase chain reaction (PCR) for the detection of food-borne pathogens General requirements and defin
30、itions (ISO 22174) Requirements for sample preparation for qualitative detection (ISO 20837) Performance testing for thermal cyclers (ISO/TS 20836) Requirements for amplification and detection for qualitative methods (ISO 20838) The International Organization for Standardization (ISO) draws attentio
31、n to the fact that it is claimed that compliance with this document may involve the use of one or more patents concerning the PCR technology. ISO takes no position concerning the evidence, validity and scope of these patent rights. ISO has been informed that Applied Biosystems, Roche Molecular Syste
32、ms, Inc. and F. Hoffman-La Roche Ltd. hold patent rights concerning the PCR technology. The companies have assured ISO that they are willing to negotiate licences under reasonable and non-discriminatory terms and conditions with applicants throughout the world. In this respect, the statements of the
33、 holders of these patent rights are registered with ISO. Information may be obtained from: Licensing Department Applied Biosystems 850 Lincoln Centre Drive Foster City, CA 94404 USA and Roche Molecular Systems, Inc. Licensing Department 1145 Atlantic Avenue Alameda, CA 94501 USA EN ISO 20838:2006vi
34、Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights other than those identified above. ISO shall not be held responsible for identifying any or all such patent rights. EN ISO 20838:20061Microbiology of food and animal feeding stuffs Po
35、lymerase chain reaction (PCR) for the detection of food-borne pathogens Requirements for amplification and detection for qualitative methods WARNING The use of this standard may involve hazardous materials, operations and equipment. This standard does not purport to address all of the safety problem
36、s associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1 Scope This International Standard provides the overall framework for qualitative methods for
37、 the detection of food-borne pathogens using the polymerase chain reaction (PCR). It covers the general requirements for the specific amplification of target nucleic acid sequences and the detection and confirmation of the identity of the amplified nucleic acid sequence. Guidelines, minimum requirem
38、ents and performance characteristics described in this International Standard are intended to ensure that comparable and reproducible results are obtained in different laboratories. This International Standard has been established for food-borne pathogens in or isolated from food and feed matrices,
39、but can also be applied to other matrices, for example environmental samples, or to the detection of other microorganisms under investigation. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cite
40、d applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 16140, Microbiology of food and animal feeding stuffs Protocol for the validation of alternative methods ISO 22174:2005, Microbiology of food and animal feeding stuffs Polymerase
41、chain reaction (PCR) for the detection of food-borne pathogens General requirements and definitions 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 22174 apply. 4 Principle For the purposes of this International Standard, qualitative analysis consist
42、s of screening and/or specific detection of target nucleic acid sequences in the test samples. Specificity can be at genus, species or a lower taxonomic level. EN ISO 20838:20062 A qualitative result shall clearly demonstrate the presence or absence of the target sequence under study, relative to ap
43、propriate controls and within the detection limits of the analytical method used and test portion analysed. The analysis generally consists of a) amplification by PCR of specific target sequences, b) detection of the PCR product, c) confirmation of the identity of the PCR product, and/or d) confirma
44、tion by a standardized microbiological cultural method (e.g. an International Standard). 5 Reagents In all cases, analytically pure reagents suitable for molecular biological applications shall be used. It is generally advisable to take aliquots of the reaction solutions required for a PCR method an
45、d to store them under appropriate conditions, for example at 20 C. 5.1 DNA polymerase A thermostable polymerase (possibly including reverse transcriptase activity) is used for PCR. This may be a purified, native enzyme, or a purified, genetically engineered recombinant form of the enzyme. It should
46、be used according to the manufacturers instructions. Each DNA polymerase may need different experimental conditions, e.g. buffer, temperature. 5.2 Reverse transcriptase This enzyme is used for transcription of RNA in complementary single-stranded DNA (cDNA) able to be amplified by a subsequent PCR.
47、It should be used according to the manufacturers instructions. 5.3 Reaction buffer The appropriate buffer should be used according to the enzyme manufacturers instructions. Ready to use reagents are commercially available. Materials used for preparation of a PCR buffer shall be stable with respect t
48、o storage and cycling conditions. It should be used according to the manufacturers instructions. 5.4 Deoxyribonucleoside triphosphates (dNTP), for PCR Solutions containing molecular biology grade dATP, dCTP, dGTP, dTTP and/or dUTP, as appropriate, shall be used. They shall be stable during storage a
49、nd under PCR conditions. They are commercially available. 5.5 Primers The primers should be selected based on a sequence specifically to detect the DNA of the target microorganism. 5.6 Water For the amplification reaction water that is DNase- and RNase-free should be used at all times. Suitable ultra pure water is available commercially. EN ISO 20838:200635.7 Magnesium chloride (MgCl2) This is supplied either as a component of the reaction buffer or as a separate solution. 5.8 C
