© ISO 2017 Sterilization of health care products — Biological indicators — Part 5 Biological indicators for low temperature steam and formaldehyde sterilization processes Stérilisation des produits de[.]
INTERNATIONAL STANDARD ISO 11138-5 Second edition 2017-03 Sterilization of health care products — Biological indicators — Part 5: Biological indicators for lowtemperature steam and formaldehyde sterilization processes Stérilisation des produits de santé — Indicateurs biologiques — Partie 5: Indicateurs biologiques pour la stérilisation la vapeur d’eau et au formaldéhyde basse température Reference number ISO 11138-5:2017(E) © ISO 2017 ISO 11138-5:2017(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2017, Published in Switzerland All rights reserved Unless otherwise specified, no part o f 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 intranet, without prior written permission Permission can be requested from either ISO at the address below or ISO’s member body in the country o f the requester ISO copyright o ffice Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii © ISO 2017 – All rights reserved ISO 11138-5:2017(E) Contents Page Foreword iv Introduction v Scope Normative references Terms and definitions General requirements Test organism Suspension Carrier and primary packaging Inoculated carriers and biological indicators Population and resistance (normative) Annex A Method for determination of resistance to low-temperature steam and formaldehyde (informative) Annex B Rationale for the liquid-phase test method for low-temperature steam and formaldehyde biological indicators Bibliography © ISO 2017 – All rights reserved iii ISO 11138-5:2017(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work o f 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 o f electrotechnical standardization The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part In particular the different approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial rules of the ISO/IEC Directives, Part (see www.iso org/directives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f 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 in formation given for the convenience o f users and does not constitute an endorsement For an explanation on the voluntary nature o f standards, the meaning o f ISO specific terms and expressions related to formity assessment, as well as in formation about ISO’s adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso org/iso/foreword html This document was prepared by Technical Committee ISO/TC 198, Sterilization of health care products This second edition cancels and replaces the first edition (ISO 11138-5:2006), which has been technically revised A list of all parts of ISO 11138 can be found on the ISO website iv © ISO 2017 – All rights reserved ISO 11138-5:2017(E) Introduction ISO 11 -1 s p e ci fie s pro duc tion, lab el l i ng , te s t me tho d s a nd p er formance re qu i rements for the manufacture of biological indicators including inoculated carriers and suspensions intended for use i n va l idation a nd mon itori ng s teri l i z ation pro ce s s e s T h i s c u ment give s s p e c i fic re qu i rements tho s e biolo gic a l i nd ic ators i ntende d for u s e i n low-temp eratu re s te am and forma ldehyde for s teri l i z ation processes Annex B f f f biological indicators The ISO 11138 series represents the current “state-of-the-art” according to the experts representing f not to promote the use of biological indicators where such use is not advised, but to provide common give s rationa le or the l iqu id-ph as e te s t me tho d or low-temp erature s te am and orma ldehyde manu ac tu rers , u s ers and regu lator y authoritie s i nvolve d i n developi ng the s tandard T he i ntent i s re qu i rements for the pro duc tion o f tho s e biolo gic a l i nd ic ators that a re known to b e i n u s e to day A standard exists providing general requirements for the validation and control of low-temperature s te am and forma ldehyde s teri l i z ation pro ce s s e s (s e e I S O 42 4) NOTE It is possible that some countries or regions have published other standards covering requirements for sterilization or biological indicators Advice on selection, use and interpretation of results when using biological indicators can be found in I S O 14161 © ISO 2017 – All rights reserved v INTERNATIONAL STANDARD ISO 11138-5:2017(E) Sterilization of health care products — Biological indicators — Part 5: Biological indicators for low-temperature steam and formaldehyde sterilization processes Scope T h i s c u ment s p e c i fie s re qu i rements for employi ng low-temp eratu re s te am and forma ldehyde te s t organ i s m s , s u s p en s ion s , i no c u l ate d c arriers , biolo gic a l indicators and test methods intended for use in assessing the performance of sterilization processes NO TE Re qu i rements for as the s teri l i z i ng agent va l id atio n a nd co ntro l o f low-temp eratu re s te a m a nd for m a ldehyde s ter i l i z ation pro ce s s e s a re p rovide d b y I S O 149 NO TE 2 T he Re qu i rements for work p l ace s a fe ty c a n b e pro vide d b y n ation a l or re gio n a l re gu l ation s Normative references fol lowi ng c u ments are re ferre d to i n the tex t i n s uch a way th at s ome or a l l o f thei r content s titute s re qu i rements o f th i s c u ment For date d re ference s , on ly the e d ition cite d appl ie s For u ndate d re ference s , the late s t e d ition o f the re ference d c ument (i nclud i ng a ny amend ments) appl ie s ISO 11138-1:2017, requirements Sterilization of health care products — Biological indicators — Part 1: General Terms and definitions ISO 11138-1 f ISO and IEC maintain terminological databases for use in standardization at the following addresses: — IEC Electropedia: available at http://www.electropedia org/ — ISO Online browsing platform: available at https://www.iso org/obp/ For the purp os es o f this cument, the terms and defi nitions given in and the ol lowing apply 3.1 low-temperature steam and formaldehyde sterilization process incorporating forced air removal, which allows exposure of wrapped goods to steam at sub- atmo s pheric pre s s u re, a nd thu s at temp eratu re s le s s th an 10 ° C , with the ad m i s s ion o f forma ldehyde gas , ke epi ng the s teri l i z i ng agent i n a s te ady s tate th roughout the hold ti me General requirements T he re qu i rements o f I S O 11 -1 apply © ISO 2017 – All rights reserved ISO 11138-5:2017(E) Test organism The test organisms shall be spores of 5.1 Geobacillus stearothermophilus or other strains of microorganisms o f demonstrated equivalent performance as required by this document NOTE Bacillus stearothermophilus has been reclassified as Geobacillus stearothermophilus NOTE Geobacillus stearothermophilus NCIB 8224, DSM 6790, ATCC 7953, ATCC 10149 and ATCC 12980 have been found to be suitable1) If a test organism other than Geobacillus stearothermophilus is used, the suitability o f the resistance of that test organism shall be determined 5.2 Suspension The requirements o f ISO 11138-1 apply Carrier and primary packaging 7.1 The suitability o f the carrier and primary packaging materials for biological indicators for use in low-temperature steam and formaldehyde sterilization processes shall be demonstrated in accordance with the requirements of ISO 11138-1:2017, 5.2 and Annex B NOTE Carriers based on filter paper might not be suitable because o f the chemisorption o f formaldehyde on cellulose surfaces The exposure conditions to determine compliance shall be the following: a) minimum exposure temperature: greater than or equal to °C above the manufacturer’s stated maximum exposure temperature; 7.2 b) maximum exposure temperature: as stated by the manu facturer; i f not stated by the manu facturer, the maximum exposure temperature shall be greater than or equal to 100 °C; c) exposure time: greater than or equal to 160 NOTE These conditions have been selected to represent a realistic challenge to the carrier while remaining within the practical limits o f a low-temperature steam and formaldehyde sterilization process Inoculated carriers and biological indicators The requirements o f ISO 11138-1 apply 9.1 Population and resistance The resistance characteristics shall be stated according to ISO 11138-1:2017, 6.4 The viable count shall be stated with increments less than or equal to 0,1 × 10 per unit (e.g per ml of suspension, per inoculated carrier or per biological indicator) 9.2 n For inoculated carriers and biological indicators, the viable count shall be greater than or equal to 1,0 × 10 9.3 1) These are examples o f suitable products available commercially This information is given for the convenience o f users o f this document and does not constitute an endorsement by ISO o f these products © ISO 2017 – All rights reserved ISO 11138-5:2017(E) 9.4 The resistance shall be expressed as the D value in mins at °C The D value of each batch/lot of b io lo gical indicato rs o r ino culated carriers s hall b e s tated in minutes to o ne decimal p lace at °C 9.5 Suspensions, inoculated carriers or biological indicators containing Geobacillus stearothermophilus spores shall have a D f Annex A Other microorganisms shall have D values supporting the application 60 9.6 value o greater than o r equal to when tes ted acco rding to the co nditio ns in The res is tance characteris tics s p ecified in this cument and any o ther p art o f I S O 1 s hall b e defined us ing the s p ecific critical variab les as s o ciated with the re ferenced s terilizatio n p ro ces s 9.7 D values are determined according to methods given in ISO 11138-1:2017, Annexes C and D Determination of D value and survival-kill response characteristics are based on the process parameters in Annex A 9.8 9.9 The survival-kill window should be calculated using the formulae in ISO 11138-1:2017, Annex E NOTE This information can be of value to the user when comparing different batches from the same manufacturer EXAMPLE Using the formulae in ISO 11138-1:2017, Annex E, with the minimum population and minimum D va lue re qu i rements s p e c i fie d i n th i s c u ment, the s u r viva l-ki l l re s p o n s e ch a rac ter i s tic s a re — at ° C : s u r viva l ti me gre ater th a n o r e qu a l to m i n a nd ki l l ti me le s s th a n or e qu a l to m i n © ISO 2017 – All rights reserved ISO 11138-5:2017(E) Annex A (normative) Method for determination of resistance to low-temperature steam and formaldehyde A.1 Principle This method is based on a qualitative test on inoculated carriers immersed in an aqueous solution of formaldehyde This method has been shown to provide more reproducible results than using a vapour phase, chamber method Specific requirements related to the test method are provided in A.3 A.2 Inoculated carrier exposure conditions The test system consists o f test tubes filled with 10 ml o f aqueous solution o f formaldehyde and held in an automatically controlled temperature water bath The test system shall be capable o f maintaining the conditions specified for exposure periods between and 150 to an accuracy A.2.1 of ±10 s A.2.2 The formaldehyde concentration o f the aqueous solution shall be determined by use o f analytical A.2.3 The method shall be validated chemical methods A.3 Procedure A.3.1 Use an aseptic technique when performing this test in order to prevent adventitious contamination Completely immerse the inoculated carriers in the test tubes filled with the formaldehyde solution at a concentration o f mol/l ± 0,01 mol/l that has been pre-heated to 60 °C ± 0,5 °C A.3.2 Ensure that the inoculated carriers are completely immersed in the formaldehyde solution and not float to the surface A.3.3 A.3.4 At the end o f the specified exposure time, remove the inoculated carriers from the formaldehyde A.3.5 Eliminate the excess liquid and immerse the carriers in the test tubes filled with a filtered solution solution of % Na2 SO for at least 10 at ambient conditions in order to inactivate formaldehyde residues on the carriers Close the test tubes Care should be taken to minimize agitation in the formaldehyde, as well as in the neutralizer solution to prevent “wash off” of test organisms NOTE Histidine and cysteine have been shown to be e ffective neutralization agents © ISO 2017 – All rights reserved ISO 11138-5:2017(E) A.3.6 NOTE The growth medium shall be specified and qualified to ensure recovery o f the test organisms Soybean casein digest medium has been found suitable for this test A.3.7 Trans fer the carriers into test tubes filled with 10 ml o f the growth medium according to A.3.6 A.3.8 Treat the test tubes for 60 at 90 °C for heat activation o f the spores A.3.9 At the end of the process, incubate the carriers (see ISO 11138-1:2017, Clause 7) Close the test tubes A.4 Determination of resistance Resistance characteristics shall be determined according to methods given in ISO 11138-1:2017, Annexes C, D and E © ISO 2017 – All rights reserved ISO 11138-5:2017(E) Annex B (informative) Rationale for the liquid-phase test method for low-temperature steam and formaldehyde biological indicators B.1 General I n order to te s t i nd ic ators i n a repro ducible man ner, s p e ci fic te s t e quipment (re s i s tome ters) and me tho d s are u s e d For the low-temp eratu re s te am and a s table forma ldehyde forma ldehyde pro ce s s , it i s ex tremely d i ffic u lt to c re ate ga s concentration i n a re s i s tome ter, s i nce defi ne d amou nts o f forma ldehyde i nj e c te d i nto a ve s s el wi l l d i s s olve i n the s ma l l a mou nts o f water d rop le ts (conden s ate) pre s ent T he concentration o f forma ldehyde i n th i s water i s 0 ti me s to 10 0 ti me s h igher i n concentration th an in the gas phase, depending on the temperature[5] It is for th i s re as on that th i s c u ment uti l i z e s a l iquid-pha s e te s t me tho d where the forma ldehyde concentration i s cle a rly defi ne d and a l lows repro duc ib le cond ition s B.2 The low-temperature steam and formaldehyde process E ven with s tant s te am cond ition s and s table forma ldehyde gas concentration s , the s teri l i z ation pro ce s s dep end s he avi ly up on the de s ign o f the s teri l i z er ch amb er and the natu re o f the lo ad T he forma ldehyde a) b) s teri l i z ation pro ce s s c a n b e s idere d s i mpl i s tic a l ly i n two s tep s: as i n s te am s teri l i z ation pro ce s s e s , an aque ou s conden s ate fi l m i s cre ate d on the s u r face o f the lo ad; NO TE T h i s conden s atio n wi l l o cc u r ver y rapid l y s i nce concentration the e xtremely d i fferent (1 : of forma ldehyde at e qu i l ibrium b e twe en 0 to : 10 0 0) , the ti me ta ken for the gas and l iqu id phas e s is th i s e qu i l ibriu m to o cc ur wi l l b e rel atively long NOTE In practical situations, this can require a time frame from 10 up to h T he le tha l ity o f the s teri l i z ation pro ce s s thu s dep end s he avi ly on the forma ldehyde concentration i n the l iquid ph as e , i e s ur face conden s ate I t c a n b e ver y d i ffic u lt to de term i ne i n ab s olute term s the ti me taken for these equilibrium conditions to be achieved © ISO 2017 – All rights reserved ISO 11138-5:2017(E) Bibliography [1] I S O 14161 , Sterilization of health care products — Biological indicators — Guidance for the selection, use and interpretation of results [2] ISO 14937, Sterilization of health care products General requirements for characterization of a [2] ISO 25424, Sterilization of medical devices — Low temperature steam and formaldehyde — Requirements for development, validation and routine control of a sterilization process for medical devices [3] EN 14180, [4] G m ann J., K aiser U., M enzel (LTSF) Sterilization Process Zentr Steril sterilizing agent and the development, validation and routine control of a sterilization process for medical devices Sterilizers for medical purposes — Low temperature steam and formaldehyde sterilizers — Requirements and testing © ISO 2017 – All rights reserved R Re ac tion ki ne tic s o f the low-temp erature - s te am- forma ldehyde 0 , (5 ) pp –2 ISO 11138-5:2017(E) ICS 1 080.01 Price based on pages © ISO 2017 – All rights reserved