BS EN ISO 21187-2004 Milk - Quantitative determination of bacteriological quality - Guidance for establishing and verifying conversion relationship between routine method results a.pdf

1、BRITISH STANDARDBS EN ISO21187:2005IncorporatingAmendment No. 1 (renumbers BS ISO 21187:2004 as BS EN ISO 21187:2005)Milk Quantitative determination of bacteriologicalquality Guidance for establishing and verifying a conversion relationship between routine method results and anchor method resultsThe

2、 European Standard EN ISO 21187:2005 has the status of a British StandardICS 07.100.30; 67.100.01g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS

3、EN ISO 21187:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 7 December 2004 BSI 14 March 2006ISBN 0 580 45010 4National forewordThis British Standard is the official English language version of EN ISO 21187:2005. It is identical with ISO

4、 21187:2004.The UK participation in its preparation was entrusted to Technical Committee AW/5, Milk and milk products, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals

5、for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or E

6、uropean publications 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 or of British Standards Online.This publication does not purport to include

7、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.Summary of pagesThis document comprises a front cover, an inside front cover, the EN ISO title page, the EN ISO

8、foreword page, the ISO title page, pages ii to vi, pages 1 to 13and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date Comments16006 March 2006 Incorporating CEN endorsement of ISO 21187EUROPEA

9、N STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 21187October 2005ICS 67.100.01; 07.100.30English VersionMilk - Quantitative determination of bacteriological quality -Guidance for establishing and verifying a conversion relationshipbetween routine method results and anchor method results (ISO21187:200

10、4)Lait - Mesure quantitative de la qualit bactriologique -Lignes directrices pour tablir et vrifier une relation deconversion entre les rsultats de la mthode de routine etles rsultats de la mthode dancrage (ISO 21187:2004)Milch - Quantitative Bestimmung der bakteriologischenQualitt - Leitfaden fr di

11、e Erarbeitung einerbertragungsbeziehung zwischen den Messwerten vonRoutine- und Bezugsverfahren sowie deren Verifizierung(ISO 21187:2004)This European Standard was approved by CEN on 30 September 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the condi

12、tions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three off

13、icial versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Be

14、lgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMI

15、T EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 21187:2005Foreword The text of ISO 21187:2004 has been prepared b

16、y Technical Committee ISO/TC 34 “Agricultural food productss” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 21187:2005 by Technical Committee CEN/TC 302 “Milk and milk products - Methods of sampling and analysis“, the secretariat of which is held by NE

17、N. 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 April 2006, and conflicting national standards shall be withdrawn at the latest by April 2006. According to the CEN/CENELEC Internal Regulations,

18、 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, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, P

19、oland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Endorsement noticeThe text of ISO 21187:2004 has been approved by CEN as EN ISO 21187:2005 without any modifications. EN ISO 21187:2005Reference numbersISO 21187:2004(E)IDF 196:2004(E)INTERNATIONALSTANDARDISO21187IDF

20、196First edition2004-12-01Milk Quantitative determination of bacteriological quality Guidance for establishing and verifying a conversion relationship between routine method results and anchor method results Lait Mesure quantitative de la qualit bactriologique Lignes directrices pour tablir et vrifi

21、er une relation de conversion entre les rsultats de la mthode de routine et les rsultats de la mthode dancrage EN ISO 21187:2005iiiiiContents PageForeword ivIntroduction . vi1 Scope 12 Normative references . 13 Terms and definitions. 14 Principles . 24.1 Prerequisites . 24.2 Organizational set-up .

22、25 Establishing a conversion relationship 35.1 Consideration of influencing factors and their consequences 35.2 Test samples . 45.3 Pretreatment of test samples. 55.4 Analysis 65.5 Calculation. 75.6 Expression of results 76 Verification of a conversion relationship . 86.1 Frequency of verification .

23、 86.2 Test samples . 86.3 Pretreatment of test samples. 86.4 Analysis 86.5 Calculation and verification of a conversion relationship 87 Test report 9Annex A (informative) Number of samples for linear regression 10Bibliography . 13EN ISO 21187:2005ivForeword ISO (the International Organization for St

24、andardization) 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 rig

25、ht 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

26、 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 International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as a

27、n International Standard requires approval by at least 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

28、21187IDF 196 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF), in collaboration with AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International. EN ISO 2118

29、7:2005vForeword IDF (the International Dairy Federation) is a worldwide federation of the dairy sector with a National Committee in every member country. Every National Committee has the right to be represented on the IDF Standing Committees carrying out the technical work. IDF collaborates with ISO

30、 and AOAC International in the development of standard methods of analysis and sampling for milk and milk products. Draft International Standards adopted by the Action Teams and Standing Committees are circulated to the National Committees for voting. Publication as an International Standard require

31、s approval by at least 50 % of the National Committees casting a vote. ISO 21187IDF 196 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF), in collaboration with AOAC International. It is being publish

32、ed jointly by ISO and IDF and separately by AOAC International. All work was carried out by the Joint ISO/IDF/AOAC Action Team, Routine analysis in quantitative microbiology, of the Standing Committee on Quality assurance, statistics of analytical data and sampling,under the aegis of its project lea

33、der, Mr H.J.C.M. van den Bijgaart (NL). EN ISO 21187:2005viIntroduction Conversion in quantitative microbiology means expressing the result of a quantitative determination of the bacteriological status of a test sample as obtained with a routine method in units of another method, generally a referen

34、ce or anchor method. Through this, quantitative results obtained with routine methods can be compared to values or limits that are stated in reference or anchor method units. For establishing and applying a conversion relationship, a number of prerequisites should be met. These are referred to in th

35、is International Standard, but are generally described elsewhere. Although a considerable part of the applied principles for conversion coincides with those applied for the calibration of indirect or routine methods against a reference method, or by means of (certified) reference materials, it is st

36、ressed that the background and aims for applying conversion are different from those for calibration. Calibration involves the determination of the adjustment needed for each level of an analyte to closely approximate the true value of its concentration or number. However in quantitative microbiolog

37、y, a true value in its strict sense cannot be established and is only defined by the method description applied. When applying routine methods in the quantitative determination of bacteriological quality, one is often dealing with different methodological principles and therefore also other units. C

38、onversion is used to transfer results obtained with different methods to a common scale. EN ISO 21187:20051Milk Quantitative determination of bacteriological quality Guidance for establishing and verifying a conversion relationship between routine method results and anchor method results 1 Scope Thi

39、s International Standard gives guidelines for the establishment of a conversion relationship between the results of a routine method and an anchor method, and its verification for the quantitative determination of the bacteriological quality of milk. 2 Normative references The following referenced d

40、ocuments 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 3534-1, Statistics Vocabulary and symbols Part 1: Probability and gener

41、al statistical termsISO 8196-1IDF 128-1, Milk Definition and evaluation of the overall accuracy of indirect methods of milk analysis Part 1: Analytical attributes of indirect methodsISO 8196-2IDF 128-2, Milk Definition and evaluation of the overall accuracy of indirect methods of milk analysis Part

42、2: Calibration and quality control in the dairy laboratory3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 3534-1, ISO 8196-1IDF 128-1, ISO 8196-2IDF 128-2 and the following apply. 3.1routine method alternative method method of analysis allowing quant

43、ification of the bacteriological status of a test sample NOTE 1 The method can be proprietary or non-commercial. NOTE 2 The term “routine” or “alternative” in this International Standard refers to the entire method. It includes all aspects (such as sample pretreatment, materials and instruments) req

44、uired for the execution of the method. NOTE 3 The term “routine method” is used in this International Standard. EN ISO 21187:200523.2anchor method reference method method of analysis internationally recognized by experts or by agreement between parties, and used, for instance, in legislation when ex

45、pressing official limits for bacteriological quality NOTE It is stressed that, in quantitative microbiology, any obtained value is only defined by the method description applied. This applies to any routine method as well as, for instance, to the standard plate count for the enumeration of microorga

46、nisms. For the purpose of conversion, the term anchor method is preferred over the term reference method and therefore is used throughout this International Standard. 3.3analyte component or property which is measured by the method of analysis NOTE The analyte may be the microorganism, stained parti

47、cles (e.g. microscopic count), components of microorganisms (e.g. lipopolysaccharides), the result of their ability to multiply (e.g. colony-forming units) or their metabolicactivity (e.g. change in conductivity/impedance). 3.4organizing laboratory laboratory, possibly appointed by the competent aut

48、horities, having the qualified staff and skills to organize, to coordinate and to report on the outcome of the activities for the establishment or the maintenance of a conversion relationship 4 Principles 4.1 Prerequisites For establishing and verifying a conversion relationship between the results

49、of a routine method and the anchor method, the following prerequisites apply. a) The routine method should have been validated according to ISO 161401). Procedures for sampling, test sample preservation, sample transport, sample storage, sample pre-treatment, analysis and calculation of results should be documented, strictly standardized and controlled in agreement with ISO/IEC 17025, EA-4/10, or comparable standards. b) The anchor method should have been validated, documented, strictly standardized and control