INTERNATIONAL STANDARD ISO 11138-1 Third edition 2017-03 Sterilization of health care products — Biological indicators — Part 1: General requirements Stérilisation des produits de santé — Indicateurs biologiques — Partie : Exigences générales Reference number ISO 11138-1:2017(E) © ISO 2017 ISO 11138-1:2017(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 11138-1:2017(E) Page Contents Foreword iv Introduction v Scope Normative references Terms and definitions General manufacturing requirements 4.1 4.4 Manufacturing controls 4.1.3 Finished product requirements 4.1.4 Personnel Test organism 4.2.1 Strain 4.2.2 Originating inoculum for suspension 4.2.3 Test organism count f f Storage and transport 5.1 5.3 5.4 5.5 Suspensions Inoculated carrier Biological indicators Self-contained biological indicators 6.1 6.2 6.3 6.4 6.5 General resistance requirements Test organism Population of test organisms Resistance characteristics Test conditions 4.2 Quality management sys tems Traceab ility I n o rmatio n to b e p rovided by the manu acturer (lab elling) Specific manu facturing requirements C arrier, p rimary and s eco ndary p ackaging Determination of population and resistance Culture conditions 10 7.1 7.2 7.3 7.4 Incubator 10 Growth medium 10 Incubation 10 Software validation 11 11 Annex A (normative) Determination of viable count 12 Annex B (normative) Determination of growth inhibition by carriers and primary 7.5 I ncub atio n time us ing detectio n sys tem packaging materials exposed to sterilization processes 14 (normative) D value determination by survivor curve method 17 Annex D (normative) D value determination by fraction negative method 21 Annex E (normative) Survival-kill response characteristics 37 Annex F (informative) Relationship between components of biological indicators 39 Annex C Bibliography 40 © ISO 2017 – All rights reserved iii ISO 11138-1:2017(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 third edition cancels and replaces the second edition (ISO 11138-1:2006), 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 11138-1:2017(E) Introduction This document specifies general requirements for production, labelling, test methods and per formance requirements for the manufacture of biological indicators including inoculated carriers and suspensions intended for use in validation and monitoring of sterilization processes Other parts of ISO 11138 provide additional specific requirements for biological indicators for defined sterilization processes A graphic description of a biological indicator and its components is presented in Table F.1 The presentation includes the two types o f biological indicators which are covered by ISO 11138 (all parts) This shows that inoculated carriers can be presented directly to the sterilizing agent without prior packaging, or included in a primary package that permits access by the sterilizing agent The resistance characteristics depend on the type o f test organism, its numbers, the method o f preparation, the substrate upon which it is inoculated, environmental conditions during inoculation and drying and the e ffects o f the primary package Advice on selection, use and interpretation o f results of biological indicators can be found in ISO 14161 For any individual sterilization process, including those covered in relevant parts o f ISO 11138, the resistance of the biological indicator will also depend on its microenvironment during testing In theory, this could lead to an infinite variation in the preparation o f biological indicators Moreover, a sterilization process could be manipulated in infinite variety to suit each possible set o f conditions to which products could be exposed It has, therefore, been a routine practice to manufacture biological indicators that, when exposed to a set o f conditions in a defined sterilization process, provide resistance characteristics expressed as D values and, where relevant, z values Such values are set out in the relevant parts of ISO 11138 The ISO 11138 series represents the current “state-of-the-art” according to the experts representing manu facturers, users and regulatory authorities involved in developing this document Biological indicators for specific sterilization processes not covered by re ference test conditions in relevant parts o f ISO 11138 should comply with the general requirements in this document, including the resistance testing procedures Such biological indicators might not be well enough described, or might be used for novel sterilization processes, or might be represented by isolated bioburden microorganisms I f microorganisms other than risk group (WHO 2004) are included in these biological indicators, appropriate sa fety measures (e.g containment) are necessary Standards exist providing requirements for the validation and control of sterilization processes (see Bibliography) NOTE It is possible that some countries or regions have published other standards covering requirements or sterilization or biological indicators (see Bibliography) f © ISO 2017 – All rights reserved v INTERNATIONAL STANDARD ISO 11138-1:2017(E) Sterilization of health care products — Biological indicators — Part 1: General requirements Scope T h i s c u ment s p e ci fie s genera l re qu i rements for pro duc tion, lab el l i ng , te s t me tho d s and p er formance characteristics of biological indicators, including inoculated carriers and suspensions, and their components, to be used in the validation and routine monitoring of sterilization processes T h i s c u ment s p e c i fie s b a s ic and com mon re qui rements th at are appl ic able to a l l p a r ts o f I S O 11 Re qu i rements for biolo gic a l i nd ic ators for p ar tic u lar s p e c i fie d pro ce s s e s a re provide d i n the relevant p a r ts o f I S O 11 I f no s p e c i fic s ub s e quent p a r t i s provide d, th i s c u ment appl ie s NO TE N ation a l or re gion a l re g u l ation s c a n ap pl y T h i s c u ment e s no t apply to m ic robiolo gic a l te s t s ys tem s o f m icro orga n i s m s , e g fi ltration pro ce s s e s for pro ce s s e s th at rely on phys ic a l remova l or pro ce s s e s th at combi ne phys ic a l a nd/or me cha n ic a l remova l with m icrobiolo gic a l i nac tivation, s uch as u s e o f wa sher d i s i n fe c tors or flu sh i ng a nd s te a m i ng of pipelines This document, however, can contain elements relevant to such microbiological test s ys tem s T he 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 11135, Sterilization of health-care products — Ethylene oxide — Requirements for the development, validation and routine control of a sterilization process for medical devices ISO 11737-1:2006, Sterilization of medical devices — Microbiological methods — Part 1: Determination of a population of microorganisms on products ISO 14937, Sterilization ofhealth care products — General requirements for characterization ofa sterilizing agent and the development, validation and routine control of a sterilization process for medical devices ISO 17665-1, Sterilization ofhealth care products — Moist heat — Part 1: Requirements for the development, validation and routine control of a sterilization process for medical devices ISO 18472, Sterilization of health care products — Biological and chemical indicators — Test equipment Terms and definitions For the pu r p o s e s o f th i s c u ment, the fol lowi ng term s and defi n ition s apply 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/ © ISO 2017 – All rights reserved ISO 11138-1:2017(E) 3.1 biological indicator te s t s ys tem co nta i n i ng vi ab le m ic ro o rga n i s m s sterilization process [SOURCE: ISO/TS 11139:2006, 2.3] pro vid i ng a de fi ne d re s i s ta nce to a s p e c i fie d 3.2 carrier supporting material on or in which test microorganisms are deposited 3.3 colony forming unit CFU individual visible units of growth of microorganisms arising from a single cell or multiple cells 3.4 culture collection number un ique identi fication collection o f the te s t organ i s m a l lo c ate d by a s cienti fic a l ly re co gni z e d s er vice c u ltu re 3.5 culture conditions combination of growth media and manner of incubation used to promote germination, growth and/or multiplication of microorganisms N o te to entr y: T he m a n ner o f i nc ub ation c a n i nclude the temp eratu re , ti me a nd a ny o ther cond itio n s s p e c i fie d for incubation [SOURCE: ISO/TS 11139:2006, 2.10] 3.6 D value D10 value time or dose required to achieve inactivation of 90 % of a population of the test microorganism under stated conditions N o te to entr y: O ther c r itic a l p ro ce s s va r iab le(s) e xh ib iti n g fi rs t o rder i n ac tivation ki ne tic s c a n ach ie ve a n inactivation of 90 % of a population of the test microorganism under stated conditions [S O U RC E : I S O/ T S 11 : 0 , 11 , mo d i fie d] 3.7 inactivation lo s s o f abi l ity o f m icro orga ni s m s to grow a nd/or mu ltiply [SOURCE: ISO/TS 11139:2006, 2.21] 3.8 inoculated carrier s upp or ti ng materi a l on or i n wh ich a defi ne d nu mb er o f viable te s t orga n i s m s have b e en dep o s ite d N o te to entr y: S e e Annex F 3.9 nominal population manufacturer’s stated number of viable microorganisms N o te to entr y: T h i s i s genera l l y e x pre s s e d i n lo g 10 function (e.g 10 ) © ISO 2017 – All rights reserved ISO 11138-1:2017(E) 3.10 primary package element o f the p ackagi ng s ys tem wh ich ma i ntai n s the i ntegrity o f the pro duc t N o te to entr y: T he p ackagi ng s ys tem pro te c ts the i no c u l ate d c a r r ier preventing penetration of the sterilizing agent from da m age a nd conta m i n ation without 3.11 process challenge device PCD item de s igne d to s titute a defi ne d performance of the process [SOURCE: ISO/TS 11139:2006, 2.33] re s i s tance to a s teri l i z ation pro ce s s and used to as s e s s 3.12 resistometer te s t e qu ipment de s igne d to cre ate defi ne d re ference combi nation s o f the phys ic a l a nd/or chem ic a l variables of a sterilization process [S OU RC E : I S O 47 : 0 , 11 , mo d i fie d] 3.13 secondary package conta i ner i n wh ich biolo gic a l i nd ic ators a re p acke d for tran s p or t and s torage 3.14 self-contained biological indicator biolo gic a l i nd ic ator pre s ente d i n s uch a way that the pri mar y p ackage, i ntende d the i nc ub ation me d iu m re qui re d for for i nc ub ation, conta i n s re cover y o f the te s t orga n i s m 3.15 survival-kill window ex tent o f e xp o s ure to a s teri l i z ation pro ce s s u nder defi ne d cond ition s where there i s a tra n s ition all biological indicators showing growth to all biological indicators showing no growth from 3.16 survivor curve graphical representation of the inactivation of a population of microorganisms with increasing exposure to a microbicidal agent under stated conditions 3.17 suspension vi able te s t organ i s m s s us p ende d i n a flu id N o te to entr y: Su s p en s ion c a n b e a b iolo gic a l i nd ic ator i f re ady to u s e i n a s e a le d gl a s s a mp o u le o r m ay b e a n intermediate component used to produce an inoculated carrier or biological indicator 3.18 viable count ac tua l nu mb er o f re coverable colony- form i ng u n its or o ther appropri ate un its N o te to entr y: S e e Annex A 3.19 z value change in exposure temperature of a thermal sterilization process, which corresponds to a tenfold change in D value N o te to entr y: S e e I S O 1 -3 a nd I S O 1 - © ISO 2017 – All rights reserved ISO 11138-1:2017(E) General manufacturing requirements 4.1 Manufacturing controls 4.1.1 Quality management systems A formal quality system (e.g ISO 13485, GMPs or other national or regional requirements) to cover all operations required by this document shall be established, documented and maintained In particular, precautions at all stages o f production to minimize contamination that would adversely a ffect the per formance o f the biological indicator shall be taken 4.1.2 Traceability 4.1.2.1 Traceability o f manu facturing components shall be maintained 4.1.2.2 Manufacturing components shall include all materials incorporated in, or coming into direct contact with, the test organism suspension, the inoculated carrier and/or its primary package 4.1.3 Finished product requirements The finished product shall comply with the following requirements: a) b) c) d) e) labelling (4.3); manufacturing (Clause 5); resistance characteristics (6.4); storage and transport (4.4); incubation (7.3) NOTE Advice on methods for the use of biological indicators is provided in ISO 14161 NOTE National and/or regional requirements might exist, for example, in the various national or regional pharmacopoeias 4.1.4 Personnel The procedures and methods in this document shall be carried out by suitably trained and experienced laboratory personnel (see e.g ISO 13485) 4.2 Test organism 4.2.1 Strain 4.2.1.1 Test organisms shall be o f a defined strain, available through a recognized culture collection, and shall be identified by appropriate test methods A statement o f traceability shall be provided to the purchaser upon request 4.2.1.2 The test organism shall be a strain that is a) suitable for handling without special containment facilities, does not need specific containment procedures for handling and does not have specific transport or mailing requirements (e.g Risk Group 1, WHO 2004), and © ISO 2017 – All rights reserved ISO 11138-1:2017(E) a = 0,25 × 18,180 = 4,545 D.3.1.3.8 The variance, V, is calculated using Formula (D.12) now that “a” is calculated: 2, 302 V= a ln N0 + 0, 577 (D.12) where N0 = × 10 ; = 4, 45 V 2 = 4, 45 V 2, ln(1 × ) + 0, 77 2, 1, + 0, 77 = 4,545 × (0,190 45) = 4,545 × 0,036 27; = 0,164 D.3.1.3.9 Dcalc The % co nfidence interval = D ±2 D.3.1.3.10 Dcalc V fo r ( = 0,05), Dcalc, is calculated using Formula (D.13): (D.13) D p Lower co nfidence limit: = D−2 = 6,54 – V 0, 164 = 6,54 – (2 × 0,4061) = 5,73 D.3.1.3.11 Dcalc Up p er co nfidence limit: = D+ = 6,54 + V 0, 164 = 6,54 + (2 × 0,406 1) = 7,35 28 © ISO 2017 – All rights reserved ISO 11138-1:2017(E) D.3.2 Limited Holcomb-Spearman-Karber procedure (LHSKP) D.3.2.1 Calculations using LHSKP D.3.2.1.1 The calculatio ns fo r LH S KP are b as ed o n a minimum o f five exp o s ure co nditio ns and s hall include at least — one set of samples in which all tested samples show growth, — two sets of samples in which a fraction of the samples shows growth, and — two sets of samples in which no growth is observed (see Table D.3) LHSK procedure is similar to HSKP (see D.3.1), except that it uses a formula which requires the same number of replicates at each exposure condition and constant time intervals between exposures D.3.2.1.2 Table D.3 — Examples of data collected for LHSKP with constant time intervals and constant number of samples Exposure time to sterilizing agent Number of test samples exposed t n (Uk ) t6 (Uk) t7 n2 n3 n4 n5 n6 n7 (U1) t2 t3 t4 t t Number of test samples showing negative results ri (r = 0) r2 r3 r4 r5 r6 (r = n) r7 (r = n) a n −1 r The test is valid if there are no negative units, i.e no negative replicates (r = 0), at the exposure preceding U1 , and all negative replicates, i.e all replicates showing a positive result (r = n) at the exposure subsequent to U a k D.3.2.1.3 The mean time to s terility, HSK = U U k where HSK − d − d n k− HSK, is calculated using Formula (D.14): U (D.14) ∑r i= i U i s the me an ti me to s teri l ity; Uk i s the fi rs t e xp o s u re to show no grow th o f the repl ic ate s; is the time or dose interval between exposures (being identical); is the number of replicates at each exposure (identical number at each exposure, e.g 20); d n k− ∑ r is the sum of the negatives between U2 and U inclusive i= i © ISO 2017 – All rights reserved k−1 29 ISO 11138-1:2017(E) The mean D value, D , can be calculated using Formula (D.15): D.3.2.1.4 D U = lo g NO TE 10 W hen (D.15) HSK N + 0, 0 fol lowi n g the me tho d ab o ve , the L H S K p ro ce du re ma ke s it p o s s ib le to c a lc u l ate the va r i a nce , , V the s ta nd a rd de viation (S D) a nd the % co n fidence i nter va l (the upp er a nd lower fidence l i m its) The variance, V, is calculated using Formula (D.16): D.3.2.1.5 V = D U 10 D.3.2.1.9 (D.18) lo wer co nfidence limit − 2SD N + 0, 0 up p er co nfidence limit HSK 10 ( = 0,05), Dcalc, is calculated using Formula (D.18): fo r D p ± 2SD HSK D U lo g (D.17) D D.3.2.1.8 lo g (D.16) i The % co nfidence interval calc = D.3.2.2 − V D.3.2.1.7 = ∑ ri (n r ) The standard deviation (SD) is calculated using Formula (D.17): SD = = n ( n − ) i =1 D.3.2.1.6 D k− d2 + 2SD N + 0, 0 Example calculations of the Limited Holcomb-Spearman-Karber procedure (LHSKP) Examples of calculation of the LHSKP are given in Table D.4 Table D.4 — Examples of data with constant time intervals and constant number of samples Exposure time to sterilizing agent Number of test samples exposed t = 20 (U1) t2 = 22 t3 = 24 t4 = 26 t5 = 28 (U ) t6 = 30 (U ) t7 = 32 t k−1 k n = 20 n = 20 n = 20 n = 20 n = 20 n = 20 n = 20 n Number of test samples showing negative results ri = (r = 0) r2 = r3 = r4 = 15 r5 = 19 r6 = 20 (r = n) a r7 = 20 (r = n) r The test is valid if there are no negative units, i.e no negative replicates (r = 0), at the exposure preceding U1 , and all negative replicates, i.e all replicates showing a positive result (r = n) at the exposure subsequent to U a k 30 © ISO 2017 – All rights reserved ISO 11138-1:2017(E) The D value is calculated using Formula (D.19): D.3.2.2.1 = D U lo g where N0 = × 10 10 (D.19) H SK N + 0, 0 The mean exposure time UHSK Formula (D.20): D.3.2.2.2 = Uk UHSK − where − k− d (D.20) ∑r n i= i = 30; = 2; = 20; Uk d n UHSK = 30 − = D D.3.2.2.3 V= d required to o b tain no growth (s terility) is calculated us ing 2 × (0 + + + + 15 + 19) = 24,8; 6, 000 + 0, 250 k −1 ∑ ri = 3,97 (rounded to one decimal place D = 4,0 min) (n − ri ) = 22 ( 20 ) ( 20 − 1) ( × × 19 ) ( + × 13 ) ( + 15 × ) ( ) + 19 × = 0, (D.21) The standard deviation (SD) is calculated using Formula (D.22): SD = V SD = 0, 107 Dcalc 20 24, n ( n − ) i =1 D.3.2.2.5 The variance, V, is calculated using Formula (D.21): d2 D.3.2.2.4 − = 0,327 (D.22) The % co nfidence intervals fo r ( = 0,05), Dcalc, is calculated using Formula (D.23): D p = D ± 2SD (D.23) U D lower fidence l i m it = lo g = © ISO 2017 – All rights reserved HSK 10 − 2SD N + 0, 24, − ( × 0, 322 ) 6, 000 + 0, 250 = 24, 144 6, 250 = 3,86 31 ISO 11138-1:2017(E) U D upp er fidence l i m it = lo g where N HSK 10 + 2SD N + 0, = 24, + ( × 0, 322 ) 6, 000 + 0, 250 = 25, 455 6, 250 =4,07 = × 10 D.3.3 The Stumbo-Murphy-Cochran-Procedure (SMCP) D.3.3.1 Procedure D.3.3.1.1 O ther metho ds o f analys ing fractio n methods of D.3.1 and D.3.2 is demonstrated negative data may b e us ed when equivalence with the SMCP, a most probable number (MPN) method, can be practical to use when the response characteristics are predictable D.3.3.1.2 The formula for SMCP requires one result in the fraction negative range consisting of time, t, the number of units negative for growth, r, the number of replicates, n , at one exposure time within the fraction negative range and the initial number of microorganisms per replicate, N0 D.3.3.1.3 To obtain valid data using SMCP, the D value should be calculated as the average of at least D.3.3.1.4 three runs in the fractio n negative range in o rder to co nfirm rep ro ducib ility D.2 D.3.3.1.5 The s ame materials ap p ly as tho s e in D.3.3.1.6 Fo r a co nfidence interval o f % , no t les s than rep licates at each exp o s ure co nditio n s hall be used and the condition r/n less than 0,9 shall be met in order to establish test criteria equivalent to D.3.1 and D.3.2 window of the batch/lot Tes t s amp les s hall b e s ub j ected to a defined exp o s ure co nditio n within the s urvival/kill D.3.3.2 Calculations using the Stumbo-Murphy-Cochran-Procedure The D value is calculated using Formula (D.24): D.3.3.2.1 D= lo g where t log10 A log10 B 32 10 t A − lo g B (D.24) 10 is the exposure time; is the log10 of initial population, N0 , per replicate; is the log10 of population after exposure time, t © ISO 2017 – All rights reserved ISO 11138-1:2017(E) Formula (D.24) can be restated for fraction negative data sets: D.3.3.2.2 t D= lo g 10 N − lo g n ln r 10 or t D= lo g 10 N − lo g 10 Nµ i where log10 Nμ = log10 (ln n/r) or log10 [2,303 log10 (n/r)] i Nu i i s the natu l lo g o f the quo tient o f the numb er o f repl ic ate s p er te s t d ivide d b y the nu m ber of negative samples; is the number of replicates per exposure time; is the number of units sterile or showing no growth n r D.3.3.2.3 D The % co nfidence interval t calc = lo g N − lo g 10 where a = r n ± 1, 96 D.3.3.2.4 D.3.3.3 r ⋅ n ( = 0,05), Dcalc, is calculated using Formula (D.25): fo r D p (D.25) () 10 - ln a 1−r/n n Formula (D.25) can o nly b e us ed i f n ×r· n n−r n is greater than or equal to 0,9 Example calculations of SMCP Table D.5 — Calculations of D value using only one data set in the fraction negative range Exposure time Number of test samples exposed Number of test samples showing no growth t n r 24 D.3.3.3.1 100 37 The D value is calculated using Formula (D.26): t D= lo g 10 A − lo g 10 B © ISO 2017 – All rights reserved (D.26) 33 ISO 11138-1:2017(E) where is the exposure time; is the initial viable count per test organism per sample = × 10 6; = log10 of initial population, N0 , per sample; = log10 of population after exposure time, t, t N or log10 A log10 B = log10 (ln n/r) or log10 [2,303 log10 (n/r)]; n is the number of replicates per exposure time; r is the number of units sterile or showing no growth 24 = D 6, 0 6, 0 D = D = 10 24 = D − lo g − lo g ( ( 10 ln 2, 70 0, 9 24 ( 6, 000 − −0, 002 24 6, 002 D.3.3.3.2 ) ) ) = 4,00 (rounded to one decimal place D = 4,0 min) The % co nfidence interval ( = 0,05), Dcalc, is calculated using the following formula fo r D p If n × r · n − r n n Formulae (D.27) and (D.28): i s gre ater tha n or e qua l to ,9, then the % fidence i nter va l c an b e c a lc u late d u s i ng D t lower fidence l i m it = lo g N − lo g where a= D r n + 1, 96 calc = r n 34 = 10 a) (D.27) r n n 24 6, 0 − lo g where a × 1− ( ln / 37 100 + 1, 96 10 37 100 ( ln / a ) × − 37 / 100 100 © ISO 2017 – All rights reserved ISO 11138-1:2017(E) 0, 63 = 37 + 1, 96 0, 37 × = 37 + 1, 96 0, 37 × 0, 006 = 37 + 1, 96 0, 002 331 = 37 + 1, 96 × 0, 048 28 , , , , a = 465 , = Dcalc 24 6, 0 = = − lo g ln 10 0, 465 24 6, 0 = 100 − lo g 10 (0 , 765 ) 24 6, 000 − ( − 115 ) , 24 6, 000 = Dcalc + 0, 115 24 6, 115 = 3,92 t D upp er fidence l i m it = lo g where a = r n Dcalc 1, 96 − = r n = × N − lo g 10 ( ln / a) (D.28) r − n n 24 6, 0 − where a 10 37 100 − 1, 96 lo g 10 37 100 ( ln / × − a) 37 / 100 100 0, 63 = , − ,9 0, 37 × = , − ,9 0, 37 × 0, 006 = , − ,9 0, 002 331 100 © ISO 2017 – All rights reserved 35 ISO 11138-1:2017(E) = , − ,9 × , 8 a = , − ,0 95 = , 75 Dcalc = 24 6, 0 = = 10 ln 0, 75 24 6, 0 − lo g 10 ( 1, ) 24 6, 000 − 0, 111 Dcalc 36 − lo g = 24 5, 889 = 4,08 © ISO 2017 – All rights reserved ISO 11138-1:2017(E) Annex E (normative) Survival-kill response characteristics E.1 Principle M on itori ng the s u r viva l-ki l l re s p on s e ch arac teri s tics o f a lo t/ b atch o f biolo gic a l i nd icators provide s an additional means of ensuring the consistent performance of units within a given lot/batch NOTE In the following subclauses and formulae of this annex, the variable “t process variable used to calculate the D value ” c a n b e rep l ace d b y a ny o ther E.2 Materials E.2.1 Tes t s amp les E.2.2 The relevant resistometer shall be used biological indicators NO TE ISO 18472 s hall be rep res entative o f s p o re s us p ens io ns , ino culated Te s t me tho d s a re gi ven i n releva nt p a r ts o f I S O 1 S p e c i fic ation s for carriers or p ackaged re s i s tome ters a re given i n E.2.3 The incub ato r s hall b e s et to p rovide, and mo nito red to co nfirm, the temp erature s p ecified in the E.2.4 The gro wth medium s hall b e as s p ecified in the culture co nditio ns culture conditions E.3 Procedure E.3.1 N o t les s than rep licates s hall b e us ed to co nfirm b o th the s urvival time and the kill time (see Table 2) The D method (see Annex D value calculated by s urvivo r curve metho d (s ee ) s hall b e us ed fo r Annex C) or a fraction negative the s tip ulatio n o f the s urvival- kill res p o ns e characteris tics For lo ts with a s i ngle ne gative biolo gica l i nd ic ator i n a s u r viva l te s t, or a s i ngle p o s itive B I i n a ki l l te s t, an add itiona l 10 s a mple s (m i ni mu m) may b e te s te d I f no add itiona l une xp e c te d re s u lts are ob tai ne d, the s u r viva l a nd ki l l ti me s a re fi rme d E.3.2 S amp les s hall b e cultured a fter exp o s ure acco rding to the manu facturer’ s s p ecified metho d The survival performance is the labelled exposure time that results in surviving test organisms test organisms of each biological indicator E.3.3 fo r each b io lo gical indicato r The kill p er fo rmance is the lab elled exp o s ure time that res ults in kill o f all E.3.4 S urvival- kill p er fo rmance characteris tics s hall b e determined in a res is to meter us ing the relevant resistometer process parameters NO TE Re ference cond itio n s © ISO 2017 – All rights reserved fo r s p e c i fic s ter i l i z atio n p ro ce s s e s a re pro vide d i n rele va nt p a r ts o f I S O 1 37 ISO 11138-1:2017(E) E.3.5 Relevant values fo r s urvival time and kill time can b e o b tained by us ing the survival time = not less than (log10 nom i na l p opu lation − ) × fo llo wing fo rmulae: D value; 10 nominal population + 4) × D value ki l l ti me = no t more than ( lo g E.3.6 The numb er o f units run per exp o s ure will dep end o n b o th the cap acity and the o p erating characteris tics o f the res is to meter being us ed I t might b e neces s ary to run s everal exp o s ures at b o th the s urvival and kill times in o rder to tes t the to tal numb er o f units required 38 © ISO 2017 – All rights reserved ISO 11138-1:2017(E) Annex F (informative) Relationship between components of biological indicators Table F.1 — Relationship between components of biological indicators Graphic illustrations Components Terminology microorganisms test organisms microorganisms suspended in test organism suspensions b flu id a microorganisms inoculated on surfaces c inoculated carrier b i no c u l ate d c a rr ier i n pr i m a r y i nd ividu a l l y p ackage d b iolo gic a l p ackage indicator growth medium with processed testing of growth properties of inoculated carrier processed inoculated carrier nation of inoculated carrier and self-contained biological indicator growth medium re ady to u s e s ys tem with co mb i unprocessed testing of growth properties of inoculated carrier NO TE T he i l lu s tratio n s re fle c t the co m mo n p hys ic a l co n fi g u ratio n s o f co mp o ne nts i n a g rap h ic a l p re s e ntatio n Te s t o rga n i s m s u s p en s io n s i n flu id s h ave the s u s p e nd i n g me d iu m a s the c a r r ier m ate r i a l , no t a s o l id m ater i a l (s e e a T he flu id emp lo ye d emp lo ye d b c fo r can va r y dep end i n g o n whe ther the m ic ro o rga n i s m s a re to be he ld fo r s to rage 3.2) purposes or te s ti n g p u r p o s e s C a n b e de fi ne d a s a b io lo g ic a l i nd ic ato r i f u s e d to mo n i to r a s ter i l i z atio n p ro ce s s In some instances the surface can be product for testing purposes © ISO 2017 – All rights reserved 39 ISO 11138-1:2017(E) Bibliography [1] ISO 8601, Data elements and interchange formats — Information interchange — Representation of [2] [3] ISO/TS 11139:2006, Sterilization of health care products — Vocabulary ISO 11140-1, Sterilization of health care products — Chemical indicators — dates and times requirements Part 1: General [4] ISO 13485, [5] ISO 14161:2009, Sterilization of health care products — Biological indicators — Guidance for the [6] ISO 15223-1, Medical devices — Symbols to be used with medical device labels, labelling and information to be supplied — Part 1: General requirements [7] [8] [9] ISO 80000 (all parts), Quantities and units IEC 60027 (all parts), Letter symbols to be used in electrical technology Armitage P., & Allen I Methods of Estimating the LD 50 in Quantal Response Data J Hyg (Lond.) 1950, XLVIII pp 298–322 C ochran W.G Estimation of Bacterial Densities by Means of the “Most Probable Number” Biometrics 1950, (1) pp 105–116 F ritze and P ukall Int J Syst Evol Microbiol 2001, 51 pp 35–37 G addum J.H Reports on biological standards, III, Methods of biological assay 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Lippincott, Williams & Wilkins, Philadelphia, 2001, pp 79–129 [22] P f lug I.J Microbiology and Engineering of Sterilization Processes Environmental Sterilization Services, Minneapolis, Eleventh Edition, 2003 [23] P f lug I.J Microbiology and Engineering of Sterilization Processes, St Paul, University o f Minnesota, 1992, ISBN O-929340-01-9 [24] Reed L.J., & M uench H.A Simple Method of Estimating Fi fty per cent Endpoints Am J Hyg 1938, 27 (3) pp 493–497 [25] S chmidt C.F Thermal resistance of microorganisms, in Antiseptics, Disinfectants, Fungicides and Sterilization (G.F Reddish, ed) 1st., pp 720-759, Lea and Febiger, Philadelphia [26] S pe arm an C The method of ‘right and wrong cases’ (‘constant stimuli’) without Gauss’s formulae Br J Psychol 1908, p 227 [27] S tumbo C.R., M urph y J.R., C ochran J Nature of Thermal Death Time Curves for P.A 3679 and Clostridium Botulinum Food Technol 1950, pp 321–326 [28] World H e alth O rganiz ation , L aboratory B iosaf ety M anual , T hird E dition WHO, Geneva, 2004 ISBN 92 154650 [29] United States Pharmacopoeia, o fficial revision and Monographs for specific BIs; , Biological Indicators — Resistance Per formance Tests: Biological Indicators for Sterilization © ISO 2017 – All rights reserved 41 ISO 11138-1:2017(E) ICS 11.080.01 Price based on 41 pages © ISO 2017 – All rights reserved