EN ISO 7932-2004 en Microbiology of food and animal feeding stuffs - Horizontal method for the enumeration of presumptive Bacillus cereus - Colony-count technique at 30 degrees C《微.pdf

1、BRITISH STANDARDBS EN ISO 7932:2004IncorporatingCorrigendum No. 1Microbiology of food and animal feeding stuffs Horizontal method for the enumeration of presumptive Bacilluscereus Colony-count technique at 30 CThe European Standard EN ISO 7932:2004 has the status of a British StandardICS 07.100.01BS

2、 EN ISO 7932:2004This British Standard waspublished under the authorityof the Standards Policy andStrategy Committee on20 December 2004 BSI August 2006ISBN 0 580 45123 2National forewordThis British Standard is the official English language version ofEN ISO 7932:2004. It is identical with ISO 7932:2

3、004. It supersedesBS EN ISO 7932:1998 and BS 4285-3.12:1989 which are withdrawn.The UK participation in its preparation was entrusted to Technical CommitteeAW/9, Microbiology, which has the responsibility to:A list of organizations represented on this committee can be obtained onrequest to its secre

4、tary.Cross-referencesThe British Standards which implement international or Europeanpublications referred to in this document may be found in the BSI Catalogueunder the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue

5、or ofBritish Standards Online.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application.Compliance with a British Standard does not of itself confer immunityfrom legal obligations. aid enquirers to understand the text; p

6、resent to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep theUK interests informed; monitor related international and European developments andpromulgate them in the UK.Summary of pagesThis document comprises a front cover, an i

7、nside front cover, the EN ISO titlepage, the EN ISO foreword page, the ISO title page, pages ii to v, a blank page,pages 1 to 13 and a back cover.The BSI copyright notice displayed in this document indicates when thedocument was last issued.Amendments issued since publicationAmd. No.16267 August 200

8、6 Revision of supersession detailsCorrigendum No. 1Date CommentsEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORMEN ISO 7932 December 2004 ICS 07.100.01 Supersedes EN ISO 7932:1997 English version Microbiology of food and animal feeding stuffs - Horizontal method for the enumeration of presumptive B

9、acillus cereus - Colony-count technique at 30 C (ISO 7932:2004) Microbiologie des aliments - Mthode horizontale pour le dnombrement de Bacillus cereus prsomptifs - Technique par comptage des colonies 30 C (ISO 7932:2004) This European Standard was approved by CEN on 17 June 2004. CEN members are bou

10、nd 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 concerning such national standards may be obtained on application to the Ce

11、ntral 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 translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status a

12、s the official versions. 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, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, S

13、pain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2004 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN nation

14、al Members. Ref. No. EN ISO 7932:2004: ENE IS97 O4002:23 E() 2Foreword This document (EN ISO 7932:2004) has been prepared by Technical Committee ISO/TC 34 “Agricultural food products“ in collaboration with Technical Committee CEN/TC 275 “Food analysis - Horizontal methods“, the secretariat of which

15、is held by DIN. 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 June 2005, and conflicting national standards shall be withdrawn at the latest by June 2005. This document supersedes EN ISO 7932 :1

16、997. 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, Ireland, Italy, Latvi

17、a, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Endorsement noticeThe text of ISO 7932:2004 has been approved by CEN as EN ISO 7932:2004 without any modifications.EN ISO 7932:2004Reference numberISO 7932:2004(

18、E)OSI 4002INTERNATIONAL STANDARDISO7932Third edition2004-06-15Microbiology of food and animal feeding stuffs Horizontal method for the enumeration of presumptive Bacillus cereus Colony-count technique at 30 C Microbiologie des aliments Mthode horizontale pour le dnombrement de Bacillus cereus prsomp

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24、EN ISO 7932:2004IS:2397 O4002(E) I SO 4002 All irthgs ersedevr iiiContents PageForeword iv0 Introduction . v1 Scope 12 Normative references . 13 Terms and definitions. 14 Principle . 15 Dilution fluid, culture media and reagents . 26 Apparatus and glassware. 47 Sampling 58 Preparation of test sample

25、. 59 Procedure. 59.1 Test portion, initial suspension and dilutions . 59.2 Inoculation and incubation 59.3 Counting of the colonies 59.4 Confirmation 610 Expression of results 610.1 Count of presumptive B. cereus colonies 610.2 No colonies 710.3 Precision 711 Test report 8Annex A (normative) Confide

26、nce limits for the estimation of small numbers of colonies. 9Annex B (informative) Results of interlaboratory test 10Bibliography . 13EN ISO 7932:2004IS:2397 O4002(E) iv I SO 4002 All irthgs ersedevrForeword ISO (the International Organization for Standardization) is a worldwide federation of nation

27、al standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. Internatio

28、nal organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rule

29、s given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at l

30、east 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 7932 was prepared by Technical Committee ISO/TC 34

31、, Food products, Subcommittee SC 9, Microbiology.This third edition cancels and replaces the second edition (ISO 7932:1993) and Technical Corrigendum 1 (ISO 7932:1993/Cor.1:1997). In this edition the previous confirmation tests mannitol/egg yolk/polymyxin (MYP) agar medium, glucose fermentation, Vog

32、es-Proskauer reaction and nitrate reduction are replaced by the following: haemolysis reaction; MYP agar medium. This edition introduces precision data obtained during an interlaboratory trial based on ISO 7932:1993 and using the following confirmation tests: MYP agar medium, glucose agar medium, VP

33、 medium and nitrate medium. EN ISO 7932:2004IS:2397 O4002(E) I SO 4002 All irthgs ersedevr v0 Introduction 0.1 This International Standard is intended to provide general guidance for the microbiological examination of food products not dealt with by existing International Standards and to be taken i

34、nto account by organizations preparing microbiological test methods for application to foods or to animal feeding stuffs. Because of the large variety of products within this field of application, these guidelines may not be appropriate in every detail for certain products and for some other product

35、s it may be necessary to use different methods. Nevertheless, it is hoped that in all cases every attempt will be made to apply the guidelines provided as far as possible and that deviations from them will only be made if absolutely necessary for technical reasons. When this International Standard i

36、s next reviewed, account will be taken of all information then available regarding the extent to which the guidelines have been followed and the reasons for deviation from them in the case of particular products. The harmonization of test methods cannot be immediate and, for certain groups of produc

37、ts, International Standards and/or national standards may already exist that do not comply with the guidelines. In cases where International Standards already exist for the product to be tested, they should be followed, but it is hoped that when such standards are reviewed they will be changed to co

38、mply with this International Standard so that eventually the only remaining departures from these guidelines will be those necessary for well-established technical reasons. 0.2 It appears that the spores of many, if not most, strains of B. cereus germinate readily on the surface of culture media use

39、d for enumeration. In most cases there does not seem to be a need for heat shock treatment to provoke germination. Sometimes a heat shock procedure is desirable, for example for spore counts or to inhibit growth of vegetative bacterial cells. In such cases, treatment for 10 min at 80 C is recommende

40、d. EN ISO 7932:2004blank4002:2397 OSI NEINTENRATIONAL TSANDADR IS:2397 O4002(E)I SO 4002 All irthgs ersedevr 1Microbiology of food and animal feeding stuffs Horizontal method for the enumeration of presumptive Bacillus cereus Colony-count technique at 30 C 1 Scope This International Standard specifi

41、es a horizontal method for the enumeration of viable presumptive Bacillus cereus by means of the colony-count technique at 30 C. It is applicable to products intended for human consumption and the feeding of animals, and environmental samples in the area of food production and food handling. NOTE In

42、 order to have a practicable test method, the confirmatory stage has been restricted to the typical aspect on MYP agar and the haemolysis test. Thus the term “presumptive” has been introduced in order to acknowledge the fact that the confirmatory stage does not enable the distinction of B. cereus fr

43、om other closely related but less commonly encountered Bacillus species, such as B. anthracis, B. thuringiensis, B. weihenstephanensis, B. mycoides. An additional motility test may help to differentiate B. cereus from B. anthracis in cases where the presence of the latter is suspected. 2 Normative r

44、eferences The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 6887-1:1999, Microbiology of food a

45、nd animal feeding stuffs Preparation of test samples, initial suspension and decimal dilutions for microbiological examination Part 1: General rules for the preparation of the initial suspension and decimal dilutionsISO 7218:1996, Microbiology of food and animal feeding stuffs General rules for micr

46、obiological examinations, and Amd.1:2001 ISO/TS 11133-2:2003, Microbiology of food and animal feeding stuffs Guidelines on preparation and production of culture media Part 2: Practical guidelines on performance testing of culture media3 Terms and definitions For the purposes of this document, the fo

47、llowing terms and definitions apply. 3.1presumptive Bacillus cereus microorganism that forms typical colonies on the surface of a selective culture medium and which gives a positive confirmation reaction under the conditions specified in this International Standard NOTE See Note in Clause 1. 4 Princ

48、iple 4.1 A specified quantity of the test sample if the initial product is liquid, or a specified quantity of an initial suspension in the case of other products, is surface plated on a solid selective culture medium contained in Petri dishes. EN ISO 7932:2004IS:2397 O4002(E) 2 I SO 4002 All irthgs

49、ersedevrOther plates are prepared under the same conditions, using decimal dilutions of the test sample or of the initial suspension. 4.2 The plates are incubated under aerobic conditions at 30 C for 18 h to 48 h. 4.3 The number of B. cereus per gram or per millilitre of sample is calculated from the number of confirmed colonies obtained on plates at dilution levels chosen so as to give a significant result, and confirmed according to the test specified. 5 Dilution fluid, cultu