DIN EN ISO 6887-5-2011 Microbiology of food and animal feeding stuffs - Preparation of test samples initial suspension and decimal dilutions for microbiological examination - Part .pdf

1、January 2011 Translation by DIN-Sprachendienst.English price group 12No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).IC

2、S 07.100.30!$m,J“1740939www.din.deDDIN EN ISO 6887-5Microbiology of food and animal feeding stuffs Preparation of test samples, initial suspension and decimal dilutions formicrobiological examination Part 5: Specific rules for the preparation of milk and milk products(ISO 6887-5:2010)English transla

3、tion of DIN EN ISO 6887-5:2011-01Mikrobiologie von Lebensmitteln und Futtermitteln Vorbereitung von Untersuchungsproben und Herstellung von Erstverdnnungen und vonDezimalverdnnungen fr mikrobiologische Untersuchungen Teil 5: Spezifische Regeln fr die Vorbereitung von Milch und Milcherzeugnissen(ISO

4、6887-5:2010)Englische bersetzung von DIN EN ISO 6887-5:2011-01Microbiologie des aliments Prparation des chantillons, de la suspension mre et des dilutions dcimales en vue delexamen microbiologique Partie 5: Rgles spcifiques pour la prparation du lait et des produits laitiers(ISO 6887-5:2010)Traducti

5、on anglaise de DIN EN ISO 6887-5:2011-01SupersedesDIN EN ISO 8261:2001-10www.beuth.deDocument comprises pagesIn case of doubt, the German-language original shall be considered authoritative.200 .11 2DIN EN ISO 6887-5:2011-01 2 A comma is used as the decimal marker. National foreword This standard ha

6、s been prepared by Technical Committee ISO/TC 34 “Food products”, Subcommittee SC 9 “Microbiology” (Secretariat: AFNOR, France) in collaboration with Technical Committee CEN/TC 275 “Food analysis Horizontal methods” (Secretariat: DIN, Germany), Working Group WG 6 “Microbiology of the food chain”. Th

7、e responsible German body involved in its preparation was the Normenausschuss Lebensmittel und landwirtschaftliche Produkte (Food and Agricultural Products Standards Committee), Working Committee NA 057-01-06 AA Mikrobiologische Lebensmitteluntersuchung einschlielich Schnellverfahren. This standard

8、is based on ISO 8261/IDF 122:2001, which was prepared by Technical Committee ISO/TC 34 “Food products” in collaboration with Technical Committee CEN/TC 302 “Milk and milk products Methods of sampling and analysis”. The standard has been renumbered as ISO 6887-5 and technically revised by ISO/TC 34/S

9、C 9. DIN EN ISO 6887 consists of the following parts, under the general title Microbiology of food and 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

10、decimal dilutions Part 2: Specific rules for the preparation of meat and meat products Part 3: Specific rules for the preparation of fish and fishery products Part 4: Specific rules for the preparation of products other than milk and milk products, meat and meat products, and fish and fishery produc

11、ts Part 5: Specific rules for the preparation of milk and milk products The following part is under preparation: Part 6: Specific rules for the preparation of samples taken at the primary production stage The DIN Standards corresponding to the International Standards referred to in Clause 2 of this

12、document are as follows: ISO 707/IDF 50 DIN EN ISO 707 ISO 6887-1 DIN EN ISO 6887-1 ISO 7218 DIN EN ISO 7218 ISO/TS 11133-2 DIN ISO/TS 11133-2 DIN EN ISO 6887-5:2011-01 3 Amendments This standard differs from DIN EN ISO 8261:2001-10 as follows: a) buffered peptone water has been included as a diluen

13、t for general use; b) the systematic pre-heating of the diluent has been kept only for those cases where it resolves problems of homogeneity of the suspension; c) the reactivation step has been deleted; d) the standard has been editorially revised and brought in line with the current rules of presen

14、tation. Previous editions DIN 10191-1: 1979-06, 1986-10 DIN 10191-2: 1979-06, 1986-10 DIN 10191-3: 1979-06, 1986-10 DIN 10191-4: 1979-06, 1986-10 DIN 10191-5: 1980-01, 1985-07 DIN EN ISO 8261: 2001-10 National Annex NA (informative) Bibliography DIN EN ISO 707, Milk and milk products Guidance on sam

15、pling DIN EN ISO 6887-1, Microbiology of food and animal feeding stuffs 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 decimal dilutions DIN EN ISO 7218, Microbiol

16、ogy of food and animal feeding stuffs General requirements and guidance for microbiological examinations DIN ISO/TS 11133-2, Microbiology of food and animal feeding stuffs Guidelines on preparation and production of culture media Part 2: Practical guidelines on performance testing of culture media D

17、IN EN ISO 6887-5:2011-01 4 This page is intentionally blank EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 6887-5 August 2010 ICS 07.100.30 Supersedes EN ISO 8261:2001English Version Microbiology of food and animal feeding stuffs - Preparation of test samples, initial suspension and decima

18、l dilutions for microbiological examination - Part 5: Specific rules for the preparation of milk and milk products (ISO 6887-5:2010) Microbiologie des aliments - Prparation des chantillons, de la suspension mre et des dilutions dcimales en vue de lexamen microbiologique - Partie 5: Rgles spcifiques

19、pour la prparation du lait et des produits laitiers (ISO 6887-5:2010) Mikrobiologie von Lebensmitteln und Futtermitteln - Vorbereitung von Untersuchungsproben und Herstellung von Erstverdnnungen und von Dezimalverdnnungen fr mikrobiologische Untersuchungen - Teil 5: Spezifische Regeln fr die Vorbere

20、itung von Milch und Milcherzeugnissen (ISO 6887-5:2010) This European Standard was approved by CEN on 25 March 2010. 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 an

21、y alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made

22、by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finlan

23、d, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOM

24、ITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 6887-5:2010: EContents DIN EN ISO 6887-5:2011-01 EN ISO 6887-5:2010 (E) 2 PageForeword3 1 Scope 4 2 Norma

25、tive references 4 3 Terms and definitions .5 4 Principle5 5 Diluents.6 6 Apparatus .10 7 Preparation of samples .10 7.1 Frozen products.10 7.2 Hard and dry products 11 7.3 Liquid and non-viscous products11 7.4 Heterogeneous products 11 8 General procedures.11 8.1 General11 8.2 Sampling.11 8.3 Genera

26、l case for acidic products.11 8.4 High-fat foods (fat content 20 % mass fraction)12 9 Specific procedures 12 9.1 Milk and liquid milk products .12 9.2 Dried milk, dried sweet whey, dried acid whey, dried buttermilk, and lactose .12 9.3 Cheese and processed cheese 12 9.4 Acid casein, lactic casein, r

27、ennet casein, and caseinate 13 9.5 Butter 14 9.6 Ice-cream 14 9.7 Custard, desserts and sweet cream (pH 5) 14 9.8 Fermented milk and sour cream (pH 5) 14 9.9 Milk-based infant foods.14 10 Further decimal dilutions15 Bibliography 16 Foreword secretariat of which is held by DIN. This European Standard

28、 shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February 2011, and conflicting national standards shall be withdrawn at the latest by February 2011. Attention is drawn to the possibility that some of the elements of th

29、is document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 8261:2001. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countri

30、es are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Sloveni

31、a, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 6887-5:2010 has been approved by CEN as a EN ISO 6887-5:2010 without any modification. DIN EN ISO 6887-5:2011-01 EN ISO 6887-5:2010 (E) 3 This document (EN ISO 6887-5:2010) has been prepared by Technical Committ

32、ee ISO/TC 34 “Food products” in collaboration with Technical Committee CEN/TC 275 “Food analysis Horizontal methods” the WARNING The use of this International Standard may involve hazardous materials, operations, and equipment. It is the responsibility of the user to establish appropriate health and

33、 safety practices and to determine the applicability of regulatory limitations prior to use. 1 Scope This part of ISO 6887 specifies rules for the preparation of samples of milk and milk products and their suspension for microbiological examination when the samples require a different preparation fr

34、om the general methods specified in ISO 6887-1. ISO 6887-1 defines the general rules for the preparation of the initial suspension and decimal dilutions for microbiological examination. This part of ISO 6887 excludes preparation of samples for both enumeration and detection test methods where prepar

35、ation details are specified in the relevant International Standards. This part of ISO 6887 is applicable to: a) milk and liquid milk products; b) dried milk products; c) cheese; d) casein and caseinates; e) butter; f) ice-cream; g) custard, desserts and sweet cream; h) fermented milk and sour cream;

36、 i) milk-based infant foods. 2 Normative references 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) applie

37、s. ISO 707IDF 50, Milk and milk products Guidance on sampling DIN EN ISO 6887-5:2011-01 EN ISO 6887-5:2010 (E) 4 ISO 6887-1, Microbiology of food and animal feeding stuffs Preparation of test samples, initial suspension and decimal dilutions for microbiological examination Part 1: General rules for

38、the preparation of the initial suspension and decimal dilutions ISO 7218, Microbiology of food and animal feeding stuffs General requirements and guidance for microbiological examinations ISO/TS 11133-2, Microbiology of food and animal feeding stuffs Guidelines on preparation and production of cultu

39、re media Part 2: Practical guidelines on performance testing of culture media 3 Terms and definitions For the purposes of this International Standard, the following terms and definitions apply. 3.1 laboratory sample sample prepared for sending to the laboratory and intended for inspection or testing

40、 NOTE Adapted from ISO 7002:19861, A.19. 3.2 test portion microbiology measured volume or measured mass of representative sample taken from the laboratory sample for use in the preparation of the initial suspension 3.3 initial suspension primary dilution suspension, solution or emulsion obtained aft

41、er a weighed or measured quantity of the product under examination (or of a test sample prepared from the product) has been mixed, if necessary, using a blender and observing appropriate precautions, with a nine-fold quantity of dilution fluid (diluent), allowing large particles, if present, to sett

42、le NOTE 1 For appropriate precautions, see 8.1. NOTE 2 For details of diluents, see Clause 5. 3.4 further decimal dilutions suspensions, solutions or emulsions obtained by mixing a specific volume of the primary dilution (3.3) with a nine-fold volume of diluent, and by repeating this operation with

43、every dilution thus prepared, until a decimal dilution series, suitable for the inoculation of culture media, is obtained 4 Principle An initial suspension (3.3) is prepared to obtain as uniform a distribution as possible of the microorganisms contained in the test sample. If necessary, further deci

44、mal dilutions (3.4) are prepared in order to reduce the number of microorganisms per volume to allow, after incubation, observation of any growth (in the case of liquid media) or colonies (in the case of agar plates), as stated in each relevant International Standard. In order to restrict, if requir

45、ed, the range of enumeration to a given interval, or if high numbers of microorganisms are foreseen, it is possible to inoculate only the necessary decimal dilutions (at least two successive dilutions) needed to achieve enumeration according to the calculation specified in ISO 7218. DIN EN ISO 6887-

46、5:2011-01 EN ISO 6887-5:2010 (E) 5 5 Diluents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade, and only sterile distilled or deionized water. 5.1 Basic materials. See ISO 6887-1. 5.2 Diluents for general use. 5.2.1 Peptone-salt solution. 5.2.1.1 Composi

47、tion. Enzymatic digest of casein 1,0 gSodium chloride (NaCl) 8,5 gWater 1 000 ml5.2.1.2 Preparation. Dissolve the components in the water, heating slightly on a hotplate (6.6) if necessary. Adjust the pH, if necessary, so that after sterilization it is 7,0 0,2 at 25 C. 5.2.2 Quarter-strength Ringers

48、 solution. 5.2.2.1 Composition. Sodium chloride (NaCl) 2,25 gPotassium chloride (KCl) 0,105 gCalcium chloride (CaCl2), anhydrous 0,06 ga Sodium hydrogencarbonate (NaHCO3) 0,05 gWater 1 000 mlaAlternatively, use 0,12 g of CaCl26H2O. 5.2.2.2 Preparation. Dissolve the salts in the water. Adjust the pH,

49、 if necessary, so that after sterilization it is 6,9 0,2 at 25 C. 5.2.3 Peptone solution. 5.2.3.1 Composition. Enzymatic digest of casein 1,0 gWater 1 000 ml5.2.3.2 Preparation. Dissolve the peptone in the water. Adjust the pH, if necessary, so that after sterilization it is 7,0 0,2 at 25 C. DIN EN ISO 6887-5:2011-01 EN ISO 6887-5:2010 (E) 6 5.2.4 Phosphate buffer solution. 5.2.4.1 Composition. Potassium dihydrogenphosphate (KH2PO4) 42,5 gWater 1 000 ml5.2.4.2 Preparation. Dissolv