BS-EN-ISO-6888-2-1999.pdf

BRITISH STANDARD BS EN ISO 6888-2:1999 Incorporating Amendment No. 1 Microbiology of food and animal feeding stuffs Horizontal method for the enumeration of coagulase-positive staphylococci (Staphylococcus aureus and other species) Part 2: Technique using rabbit plasma fibrinogen agar medium The European Standard EN ISO 6888-2:1999, with the incorporation of amendment A1:2003, has the status of a British Standard ICS 07.100.30 ? Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 09:53:17 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 6888-2:1999 This British Standard, having been prepared under the direction of the Consumer Products and Services Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 May 1999 © BSI 23 October 2003 ISBN 0 580 32307 2 National foreword This British Standard is the English language version of EN ISO 6888-2:1999, including amendment A1:2003. It is identical with ISO 6888-2:1999, including amendment 1:2003. Together with Part 1, it supersedes BS 5763-7:1983 which is withdrawn. The start and finish of text introduced or altered by amendment is indicated in the text by tags !“. Tags indicating changes to CEN text carry the number of the CEN amendment. For example, text altered by CEN amendment A1 is indicated by !“. The UK participation in its preparation was entrusted to Technical Committee AW/9, Microbiology, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The 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 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 immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This 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 iv, pages 1 to 11 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No.DateComments 1459123 October 2003See national foreword Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 09:53:17 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN ISO 6888-2 February 1999 + A1 July 2003 ICS 07.100.30 English version Microbiology of food and animal feeding stuffs Horizontal method for the enumeration of coagulase-positive staphylococci (Staphylococcus aureus and other species) Part 2: Technique using rabbit plasma fibrinogen agar medium (includes amendment A1:2003) (ISO 6888-2:1999 + A1:2003) Microbiologie des aliments Méthode horizontale pour le dénombrement des staphylocoques à coagulase positive (Staphylococcus aureus et autres espèces) Partie 2: Technique utilisant le milieu gélosé au plasma de lapin et au fibrinogène (inclut lamendement A1:2003) (ISO 6888-2:1999 + A1:2003) Mikrobiologie von Lebensmitteln und Futtermitteln Horizontales Verfahren für die Zählung von koagulase-positiven Staphylokokken (Staphylococcus aureus und andere Spezies) Teil 2: Verfahren mit Kaninchenplasma/Fibrinogen-Agar (enthält Änderung A1:2003) (ISO 6888-2:1999 + A1:2003) This European Standard was approved by CEN on 15 February 1999. Amendment A1 was approved by CEN on 2 June 2003. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard 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 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 translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels © 1999 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 6888-2:1999 + A1:2003 E Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 09:53:17 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 6888-2:1999 © BSI 23 October 2003 Foreword The text of the International Standard ISO 6888-2:1999 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 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 August 1999, and conflicting national standards shall be withdrawn at the latest by August 1999. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of the International Standard ISO 6888-2:1999 was approved by CEN as a European Standard without any modification. Foreword to amendment A1 This document EN ISO 6888-2:1999/A1:2003 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 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 January 2004, and conflicting national standards shall be withdrawn at the latest by January 2004. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 6888-2:1999/Amd 1 has been approved by CEN as EN ISO 6888-2:1999/A1:2003 without any modifications. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 09:53:17 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 09:53:17 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 6888-2:1999 ii © BSI 23 October 2003 Contents Page Forewordiii 1Scope1 2Normative references1 3Terms and definitions2 4Principle2 5Diluent and culture media2 6Apparatus and glassware3 7Sampling4 8Preparation of test sample4 9Procedure4 10Expression of results4 11Precision6 12Test report7 Annex A (informative) Results of the interlaboratory study8 Bibliography11 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 09:53:17 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 6888-2:1999 © BSI 23 October 2003 iii 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 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. International 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 rules given in the ISO/IEC Directives, Part 3. 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 least 75 % of the member bodies casting a vote. International Standard ISO 6888-1 was prepared by Technical Committee ISO/TC 34, Agricultural food products, Subcommittee SC 9, Microbiology. This first edition of ISO 6888-2, together with ISO 6888-1, cancels and replaces ISO 6888:1983, which has been technically revised. ISO 6888 consists of the following parts, under the general title Microbiology of food and animal feeding stuffs Horizontal method for the enumeration of coagulase-positive staphylococci (Staphylococcus aureus and other species): Part 1: Technique using Baird-Parker agar medium; Part 2: Technique using rabbit plasma fibrinogen agar medium. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 09:53:17 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 09:53:17 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 6888-2:1999 © BSI 23 October 2003 1 0 Introduction 0.1 Because of the large variety of food and feed products, this horizontal method may not be appropriate in every detail for certain products. In this case, different methods, which are specific to these products may be used if absolutely necessary for justified technical reasons. Nevertheless, every attempt should be made to apply this horizontal method as far as possible. When this part of ISO 6888 is next reviewed, account will be taken of all information then available regarding the extent to which this horizontal method has been followed and the reasons for deviations from this method in the case of particular products. The harmonization of test methods cannot be immediate, and for certain groups of products International Standards and/or national standards may already exist that do not comply with this horizontal method. It is hoped that when such standards are reviewed they will be changed to comply with this part of ISO 6888 so that eventually the only remaining departures from this horizontal method will be those necessary for well-established technical reasons. 0.2 ISO 6888 describes two horizontal methods (Part 1 and Part 2) for the enumeration of coagulase-positive staphylococci among which enterotoxinogenic strains are encountered. It is mainly concerned with Staphylococcus aureus, but also with S. intermedius and certain strains of S. hyicus. !Both parts of ISO 6888 are given equivalent status. Nevertheless, it is recommended to use the procedure described in ISO 6888-2 for the foods (such as cheeses made from raw milk and certain raw meat products) likely to be contaminated by:“ staphylococci forming atypical colonies on a Baird-Parker agar medium; background flora which can obscure the colonies being sought. 0.3 For the purposes of this part of ISO 6888, the characterization of staphylococci is based on a positive- coagulase reaction, but it is recognized that some strains of Staphylococcus aureus give weakly positive coagulase reactions. These latter strains may be confused with other bacteria but they may be distinguished from such other bacteria by the use of additional tests not included in this part of ISO 6888, such as the sensitivity to lysostaphin, the production of haemolysin, of thermostable nuclease and of acid from mannitol (see reference 1). 1 Scope This part of ISO 6888 describes a horizontal method for the enumeration of coagulase-positive staphylococci in products intended for human consumption or feeding of animals by counting of colonies obtained on a solid medium (rabbit plasma fibrinogen medium) after aerobic incubation at 35 °C or 37 °C (see reference 2). 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 6888. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of ISO 6888 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 6887-1, Microbiology of food and animal feeding stuffs Rules for the preparation of the test samples, of initial suspension and of decimal dilutions for microbiological examination Part 1: General rules for the preparation of the initial suspension and of decimal dilutions. ISO 6888-1:1999, Microbiology of food and animal feeding stuffs Horizontal method for the enumeration of coagulase positive staphylococci (Staphylococcus aureus and other species) Part 1: Technique using Baird-Parker agar medium. ISO 7218, Microbiology of food and animal feeding stuffs General rules for microbiological examinations. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 17 09:53:17 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 6888-2:1999 2© BSI 23 October 2003 3 Terms and definitions For the purposes of this part of ISO 6888, the following terms and definitions apply. 3.1 coagulase-positive staphylococci bacteria which form typical colonies in a rabbit plasma fibrinogen selective agar medium when the test is carried out according to the method specified in this part of ISO 6888 3.2 enumeration of the coagulase-positive staphylococci determination of the number of coagulase-positive staphylococci found per millilitre or per gram of sample when the test is carried out according to the method specified in this part of ISO 6888 4 Principle 4.1 Preparation of duplicate poured plates of the rabbit plasma fibrinogen agar medium, with a specified quantity of the test sample if the product is liquid or with a specified qua