1、Synthetic rubber latex Examination for microorganismsBS ISO 20851:2017BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06 ISO 2017Synthetic rubber latex Examination for microorganismsLatex de caoutchouc synthtique Examen des micro-organismesINTERNATIONAL STANDARDISO2085
2、1First edition2017-07Reference numberISO 20851:2017(E)National forewordThis British Standard is the UK implementation of ISO 20851:2017.The UK participation in its preparation was entrusted to Technical Committee PRI/50, Raw materials (including latex) for use in the rubber industry.A list of organi
3、zations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017
4、ISBN 978 0 580 92828 4ICS 83.040.10Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 September 2017.Amendments/corrigenda issued since publicationDate Text affe
5、ctedBRITISH STANDARDBS ISO 20851:2017 ISO 2017Synthetic rubber latex Examination for microorganismsLatex de caoutchouc synthtique Examen des micro-organismesINTERNATIONAL STANDARDISO20851First edition2017-07Reference numberISO 20851:2017(E)BS ISO 20851:2017ISO 20851:2017(E)ii ISO 2017 All rights res
6、ervedCOPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an int
7、ranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww
8、.iso.orgBS ISO 20851:2017ISO 20851:2017(E)ii ISO 2017 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mech
9、anical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, Swi
10、tzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgISO 20851:2017(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Reagent . 26 Apparatus . 27 Sampling 28 Procedure. 29 Examination 39.1 Examination of the microbial count
11、 (CFU/ml) 39.2 Interpretation 310 Disposal of the used slides and equipment 311 Test report . 3Annex A (informative) Example of a model chart . 4Annex B (informative) Interpretation of the microbial count . 5 ISO 2017 All rights reserved iiiContents PageBS ISO 20851:2017ISO 20851:2017(E)ForewordISO
12、(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 comm
13、ittee 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 electrote
14、chnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafte
15、d in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).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 ri
16、ghts. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents).Any trade name used in this document is information given for the convenience of users and does not con
17、stitute an endorsement.For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) se
18、e the following URL: www .iso .org/ iso/ foreword .htmlThis document was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 3, Raw materials (including latex) for use in the rubber industry.iv ISO 2017 All rights reservedBS ISO 20851:2017ISO 20851:2017(E)ForewordI
19、SO (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 c
20、ommittee 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 electr
21、otechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was dra
22、fted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).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
23、 rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents).Any trade name used in this document is information given for the convenience of users and does not
24、constitute an endorsement.For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT)
25、 see the following URL: www .iso .org/ iso/ foreword .htmlThis document was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 3, Raw materials (including latex) for use in the rubber industry.iv ISO 2017 All rights reserved ISO 20851:2017(E)IntroductionSynthetic
26、latices are susceptible to post-production contamination with microorganisms during storage and shipment. Unless precautions are taken, such as maintenance of a high pH, the addition of biocide and inspection and cleaning of tanks, these organisms may proliferate, ultimately producing unpleasant odo
27、urs and changes in the chemical and physical properties of the latex. It is highly desirable to be able to detect the presence of significant microorganisms before such changes develop.This document replaces ISO 9252:1989, Synthetic rubber latex Microbiological examination, which was withdrawn due t
28、o its obsolescence and complicated testing procedures. This document provides a far more simplified method for the purpose of microbiological examination, employing a ready-made medium slide as reagent. ISO 2017 All rights reserved vBS ISO 20851:2017Synthetic rubber latex Examination for microorgani
29、smsWARNING 1 Persons using this document should be familiar with normal laboratory practice. This document does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure
30、compliance with any national regulatory conditions.WARNING 2 Certain procedures specified in this document might involve the use or generation of substances, or the generation of waste, that could constitute a local environmental hazard. Reference should be made to appropriate documentation on safe
31、handling and disposal after use.1 ScopeThis document specifies the method to examine the presence and approximate count of viable aerobic and facultative anaerobic microorganisms in synthetic rubber latices.Identification of the microorganisms is outside the scope of this document.2 Normative refere
32、ncesThe following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) ap
33、plies.ISO 123, Rubber latex SamplingISO 7218, Microbiology of food and animal feeding stuffs General requirements and guidance for microbiological examinations3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.ISO and IEC maintain terminological datab
34、ases for use in standardization at the following addresses: IEC Electropedia: available at h t t p :/ www .electropedia .org/ ISO Online browsing platform: available at h t t p :/ www .iso .org/ obp3.1colonygroup of microbial cells derived, ideally, by the multiplication of a single organism4 Princi
35、pleThe slide with the medium surfaces is dipped in the test portion of the latex. The microorganisms on both sides of the slide are incubated for a certain amount of time at a regulated temperature.After incubation, the approximate number of microorganisms is determined by comparing the density of t
36、he growth of colony on the slide with the model chart.The approximate count is expressed in colony forming unit per millilitre (CFU/ml).INTERNATIONAL STANDARD ISO 20851:2017(E) ISO 2017 All rights reserved 1BS ISO 20851:2017Synthetic rubber latex Examination for microorganismsWARNING 1 Persons using
37、 this document should be familiar with normal laboratory practice. This document does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any nation
38、al regulatory conditions.WARNING 2 Certain procedures specified in this document might involve the use or generation of substances, or the generation of waste, that could constitute a local environmental hazard. Reference should be made to appropriate documentation on safe handling and disposal afte
39、r use.1 ScopeThis document specifies the method to examine the presence and approximate count of viable aerobic and facultative anaerobic microorganisms in synthetic rubber latices.Identification of the microorganisms is outside the scope of this document.2 Normative referencesThe following document
40、s are referred to in the text in such a way that some or all of their content constitutes requirements 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 123, Rubber late
41、x SamplingISO 7218, Microbiology of food and animal feeding stuffs General requirements and guidance for microbiological examinations3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.ISO and IEC maintain terminological databases for use in standardiz
42、ation at the following addresses: IEC Electropedia: available at h t t p :/ www .electropedia .org/ ISO Online browsing platform: available at h t t p :/ www .iso .org/ obp3.1colonygroup of microbial cells derived, ideally, by the multiplication of a single organism4 PrincipleThe slide with the medi
43、um surfaces is dipped in the test portion of the latex. The microorganisms on both sides of the slide are incubated for a certain amount of time at a regulated temperature.After incubation, the approximate number of microorganisms is determined by comparing the density of the growth of colony on the
44、 slide with the model chart.The approximate count is expressed in colony forming unit per millilitre (CFU/ml).INTERNATIONAL STANDARD ISO 20851:2017(E) ISO 2017 All rights reserved 1 ISO 20851:2017(E)5 ReagentDuring the analysis, use only reagents of recognized analytical grade and only distilled wat
45、er or water of equivalent purity.5.1 Medium slide1), designed to examine the count of viable aerobic and facultative anaerobic microorganisms, usually stored in a tube.NOTE Typical formulation of the medium includesa) TTC (2,3,5-Triphenyl 2H-tetrazolium chloride),b) agar, andc) tryptone and/or pepto
46、ne.5.2 1 % (mass fraction) sodium hypochlorite solution, as disinfectant.6 ApparatusStandard laboratory equipment and the following.6.1 Incubator, capable of maintaining a temperature of 28 C 1 C or 36 C 1 C.6.2 Autoclave, capable of maintaining a temperature of 121 C 1 C, as described in ISO 7218.6
47、.3 Absorbent paper.7 SamplingSampling shall be carried out as described in ISO 123, using disposable pre-sterilized equipment or equipment sterilized in accordance with ISO 7218.8 ProcedureUnless otherwise instructed by the manufacturers, a typical procedure is described hereafter. Operations shall
48、be carried out in accordance with the instruction by the manufacturer of the medium slide.a) Agitate the sample thoroughly.b) Unscrew the tube and withdraw the slide without touching the medium surfaces.c) Inspect both sides of the slide to determine if there are any defects on the growth media such
49、 as discoloration or detachment from the plastic slide.d) Dip the slide in the sample for approximately 5 s to have both sides of the slide completely wet. If the viscosity of the sample is high, dilute the sample with sterile water and record the dilution factor, F.e) Drain off excess sample and blot the last drops from the lower end of the slide on absorbent paper (6.3).f) Screw the medium slide tightly back into the tube.1) SAN-AI BIOCHECKER TTC supplied by SAN-AI OIL CO., LTD. (www .san -a
