11737-1

American National Standard d me mi AAMI Sterilizatio evicesMi thodsPa of the po croorganis ANSI/AAMI/ISO 11737-1:1995 Association for the Advancement of Medical Instrumentation n of medical crobiological rt 1: Estimation pulation of ms on product Association for the Advancement of Medical Instrumentation 1110 N. Glebe Rd., Suite 220 Arlington, VA 22201-4795 © 2000 by the Association for the Advancement of Medical Instrumentation All Rights Reserved Copyright and Permissions Publication, reproduction, photocopying, storage, or transmission, electronically or otherwise, of all or any part of these documents without the prior written permission of the Association for the Advancement of Medical Instrumentation or the copyright holder (if not AAMI) is prohibited by law. It is illegal under federal law (17 U.S.C. § 101, et seq.) to make copies of all or any part of these documents (whether internally or externally) without the prior written permission of the copyright holder. Violators risk legal action, including civil and criminal penalties, and damages of $100,000 per offense. For permission regarding the use of all or any part of these documents, contact AAMI, 1110 N. Glebe Road, Suite 220, Arlington, VA 22201-4795. Phone: (703) 525-4890; Fax: (703) 525-1067. Violators of this copyright policy should be reported to AAMI’s legal counsel: McKenna & Cuneo, L.L.P. 1900 K Street, N.W. Washington, DC 20006 Attn: Jacqueline A. Henson, Esq. Phone: (202) 496-7500 11737-1 Estimation of Population of Microorganisms on Products American National Standard ANSI/AAMI/ISO 11737-1—1995 Sterilization of medical devices—Microbiological methods—Part 1: Estimation of population of microorganisms on products Approved 24 July 1995 by Association for the Advancement of Medical Instrumentation Approved 11 September 1995 by American National Standards Institute, Inc. Abstract: This standard specifies general criteria to be applied in the estimation of the population of viable microorganisms on a medical device or component, raw material or package thereof. This estimation consists of both enumeration and characterization of the population. Association for the Advancement of Medical Instrumentation The adoption of this International Standard as an American National Standard was approved by the AAMI Microbiological Methods Working Group, under the auspices of the AAMI Sterilization Standards Committee. Committee approval of the recommended practice does not necessarily imply that all committee, sub-committee, and working group members voted for its approval. The AAMI Sterilization Standards Committee has the following members: Cochairs: Carl W. Bruch, PhD Virginia C. Chamberlain, PhD Members: Carl W. Bruch, PhD, Consultant, Hudson, WI Virginia C. Chamberlain, PhD, Center for Devices and Radiological Health, Food and Drug Administration Neal E. Danielson, HCA Wesley Medical Center, Wichita, KS Judith C. Dowler, Medical Devices Bureau, Health Canada, Ottawa, ON Frank B. Engley, Jr., PhD, Univ. Missouri School of Medicine, Columbia, MO Collette P. Keyser, RN, Alexandria, VA (Colonel, U.S. Army, Retired) Robert F. Morrissey, PhD, Johnson & Johnson Barry F.J. Page, Consultant, Garner, NC Marimargaret Reichert, RN, MA, Reichert Consulting, Olmsted Falls, OH Janet K. Schultz, RN, AMSCO International James Whitbourne, Sterilization Technical Services James L. Whitby, MA, MB, FRCP, Univ. Of Western Ontario, London, ON The AAMI Microbiological Methods Working Group has the following members: Cochairs: Trabue D. Bryans Harry L. Shaffer Members: Krisann Anderson, St. Jude Medical, St. Paul, MN Edward Arscott, North American Science Associates, Inc. © 2000 Association for the Advancement of Medical Instrumentation Joy Barnitz, Bausch & Lomb, Inc. Anne F. Booth, MS, Booth & Associates, Barrington, IL Trabue D. Bryans, Practical Consulting and Training, Kennesaw, GA Virginia C. Chamberlain, PhD, Center for Devices and Radiological Health, Food and Drug Administration Gary N. Cranston, Consulting & Technical Services Douglas D. Davie, Sterilization Validation Services Joyce M. Hansen, Baxter Healthcare Corporation Deborah Havlik, Griffith Micro Science, Inc. Craig M. Herring, Johnson & Johnson Mary S. Mayo, C. R. Bard, Inc. John Nygard, Advanced Bio-Control Technologies Gordon S. Oxborrow, 3M Robert R. Reich, Pharmaceutical Systems, Inc. Zenius V. Seliokas, Davis & Geck Company Harry L. Shaffer, Titan Corporation Robert Tomaselli, Convatec, Bristol-Myers Squibb Thelma Wilcott, Becton Dickinson & Company Alternates: Richard H. Bean, Bristol-Myers Squibb Daniel J. Burgess, Pharmaceutical Systems, Inc. NOTE—Participation by federal agency representatives in the development of this standard does not constitute endorsement by the federal government or any of its agencies. Background of ANSI/AAMI adoption of ISO 11737-1:1995 Sterilization of medical devices — Microbiological methods — Part 1: Estimation of population of microorganisms on products The International Organization for Standardization (ISO) is a worldwide federation of national standards bodies. The United States is one of the ISO members that took an active role in the development of this standard. ISO 11737-1 was developed by ISO Technical Committee (TC) 198, Sterilization of health care products to fill a need for an international standard for the estimation of the population of microorganisms on medical devices. TC 198 approved the standard in 1995, and it was published by ISO in 1995. United States participation in ISO/TC 198 is organized through the U.S. Technical Advisory Group for ISO/TC 198, administered by the Association for the Advancement of Medical Instrumentation (AAMI). AAMI also administers the Secretariat for TC 198 on behalf of the United States, which made a considerable contribution to this standard and holds the convenership of the responsible international working group. AAMI encourages its committees to harmonize their work with international standards as much as possible. The proposal to adopt ISO 11737-1 in the United States was made by the AAMI Microbiological Methods Working Group. At the time part 1 was published in the United States, the working group was reviewing ISO/DIS 11737-2, Sterilization of medical devices—Microbiological methods—Part 2: Tests of sterility performed in the validation of a sterilization process, for adoption as a new American National Standard. Part 2 specifies the general criteria for tests of sterility on medical devices that have been exposed to a treatment with the sterilizing agent, which is a fraction of the specified sterilization process, and upon finalization will supersede AAMI TIR 8, Microbiological methods for gamma irradiation sterilization of medical devices. © 2000 Association for the Advancement of Medical Instrumentation AAMI (and ANSI) have adopted other ISO standards, some of which are referenced in this document. See the next page for a list of ISO standards adopted by AAMI, the corresponding U.S. designation, and the level of equivalency with the ISO standard. The concepts incorporated in this standard should not be considered inflexible or static. In addition, AAMI and ANSI procedures require that standards be reviewed and, if necessary, revised every 5 years, and this standard, like any other, will be updated periodically to assimilate progressive technological developments as new data come to light. Suggestions for improving this standard are invited. Comments and suggested revisions should be sent to Standards Department, AAMI, 3330 Washington Boulevard, Suite 400, Arlington, VA 22201. NOTE—Beginning with the ISO foreword on page vii, this American National Standard is identical to ISO 11737-1:1995. Foreword ISO (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 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 of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75% of the member bodies casting a vote. International Standard ISO 11737-1 was prepared by Technical Committee ISO/TC 198, Sterilization of health care products, and is based on three European Standard drafts prepared by Working Group 5 of CEN Technical Committee 204, Sterilization of medical devices. ISO 11737 currently consists of the following parts, under the general title Sterilization of medical devices—Microbiological methods: — Part 1: Estimation of the population of microorganisms on products — Part 2: Tests of sterility performed in the validation of a sterilization process Additional parts will be published later. Annexes A, B, and C of this part of ISO 11737 are for information only. Introduction A sterile product item is one which is free of viable microorganisms. The International Standards for sterilization of health care products require, when it is necessary to supply a sterile product item, that adventitious microbiological contamination of a health care product from all sources is minimized by all practical means. Even so, product items produced under standard manufacturing conditions in accordance with the requirements for quality systems for health care products may, prior to sterilization, have microorganisms on them, albeit in low numbers. Such product items are nonsterile. The purpose of sterilization processing is to inactivate the microbiological contaminants and thereby transform the nonsterile items into sterile ones. The inactivation of a pure culture of microorganisms by physical and/or chemical agents used to sterilize health care products often approximates to an exponential relationship; inevitably this means that there is always a finite probability that a microorganism may survive regardless of the extent of treatment applied. © 2000 Association for the Advancement of Medical Instrumentation For a given treatment, the probability of survival is determined by the number and resistance of microorganisms and by the environment in which the organisms exist during treatment. It follows that the sterility of any one item in a population of items subjected to sterilization processing cannot be guaranteed and the sterility of the processed population of items has to be defined in terms of the probability of the existence of a nonsterile item in that population. Requirements for the quality system for the design/development, production, installation and servicing of health care products are given in ISO 9001 and ISO 9002. The ISO 9000 series of International Standards designates certain processes used in manufacture as "special" if the results cannot be fully verified by subsequent inspection and testing of the product. Sterilization is an example of a special process because process efficiency cannot be verified by inspection and testing of the product. For this reason, sterilization processes have to be validated before use, the performance of each process monitored routinely and the equipment properly maintained. International Standards specifying procedures for the validation and routine control of the processes used for the sterilization of health care products have been prepared (see ISO 11134, ISO 11135 and ISO 11137). However, it is important to be aware that exposure to a properly validated and accurately controlled sterilization process is not the only factor associated with the provision of assurance that the product is sterile and, in this respect, suitable for its intended use. Indeed for the effective validation and routine control of a sterilization process, it is also important to be aware of the microbiological challenge which is presented to that process, in terms of number, identities and properties of microorganisms. The presterilization microbiological contamination is the sum of contributions from a number of sources; therefore attention also has to be given to factors including the microbiological status of incoming raw materials and/or components and their subsequent storage, and to the control of the environment in which the product is manufactured, assembled and packaged. The term "bioburden" is commonly used to describe the population of viable microorganisms present on a material or product. It is not possible to determine the exact bioburden and therefore, in practice, a viable count is determined using a defined technique. Validation exercises are performed to relate this viable count to a bioburden estimate on a material or product by the application of a correction factor. The knowledge of the bioburden results from the investigation of microbiological contamination levels. Bioburden estimations are performed in a number of separate situations as part of the: a) validation and revalidation of a sterilization process for which the extent of exposure to sterilizing conditions is to be directly related to the bioburden estimate; b) validation and revalidation of a sterilization process for which the extent of exposure to sterilizing conditions is not to be directly related to the bioburden estimate, but for which a general knowledge of bioburden is required; c) routine control of the manufacturing process for a sterile product for which sterilization validation was as stated in a) above; d) routine control of the manufacturing process for a sterile product for which sterilization validation was as stated in b) above. Bioburden estimations may also be employed as part of the quality system for the manufacture of health care products as an element of: e) an overall environmental monitoring program; f) the assessment of the efficiency of a cleaning process in removing microorganisms; g) the process monitoring for products which are supplied nonsterile but for which the microbiological © 2000 Association for the Advancement of Medical Instrumentation cleanliness is specified; h) the monitoring of raw materials, components or packaging. The bioburden estimation of a medical device generally consists of four distinct stages: — removal of microorganisms from the medical device; — transfer of these isolated microorganisms to culture conditions; — enumeration of the microorganisms with subsequent characterization; — application of the correction factor(s) determined during bioburden recovery studies in order to calculate the bioburden estimate from the presterilization count. It is not possible to define a single technique to be used for the removal of microorganisms in all situations because of the wide variety of materials for construction and design of health care products. Furthermore, the selection of conditions for enumeration will be influenced by the types of contaminant which may be anticipated. This part of ISO 11737 therefore specifies the general criteria to be applied to the estimation of bioburden. The annexes of this part of ISO 11737 provide additional guidance (annex A) and methods which may be used for validating the technique (annex B). Sterilization of medical devices— Microbiological methods—Part 1: Estimation of population of microorganisms on products 1 Scope 1.1 This part of ISO 11737 specifies general criteria to be applied in the estimation of the population of viable microorganisms on a medical device or component, raw material or package thereof. This estimation consists of both enumeration and characterization of the population. NOTES 1 Prior to routine use, a technique for estimating the population of microorganisms on product is validated. The level to which identification is necessary during characterization depends on the use to be made of the data generated. 2 Annexes to this part of ISO 11737 provide guidance on selection of a technique and outline method(s) which may be used to validate the technique selected. 1.2 This part of ISO 11737 is not applicable to the enumeration or identification of viral contamination. This part of ISO 11737 is not applicable to the microbiological monitoring of the environment in which medical devices are manufactured. NOTE 3 Attention is drawn to the International Standards for quality systems (see ISO 9001 and ISO 9002) which control all stages of manufacture including the sterilization process. It is not a requirement of this part of ISO 11737 to have a complete quality system during manufacture, but certain elements of such a system are required and these are normatively referenced at appropriate places in the text. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this part of ISO 11737. At the time of publication, the edition indicated was valid. All standards are subject © 2000 Association for the Advancement of Medical Instrumentation to revision, and parties to agreements based on this part of ISO 11737 are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of the IEC and ISO maintain registers of currently valid International Standards. ISO 9001:1994, Quality systems—Model for quality assurance in design, development, production, installation and servicing. 3 Definitions For the purposes of this part of ISO 11737, the following definitions apply. 3.1 bioburden: Population of viable microorganisms on a product and/or a package. 3.2 bioburden estimate: Value established for the number of microorganisms comprising the bioburden by applying to a viable count or presterilization count a factor compensating for the recovery efficiency. 3.3 characterization: General process in which microorganisms are grouped into broad categories. NOTE 4 Categories may be based, for example, on colony or cellular morphology, staining properties or other characteristics. 3.4 correction factor: Numerical value applied to a viable count or presterilization count to compensate for the incomplete removal of microorganisms from product and thus produce a bioburden estimate. 3.5 culture conditions: Stated combination of conditions, including the growth medium with the period and temperature of incubation, used to promote growth and multiplication of microorganisms. 3.6 medical device: Any instrument, apparatus, appliance, material or other article, whether used alone or in combination, including the software necessary for its proper application, intended by the manufacturer to be used for human beings for the purposes of — diagnosis, prevention, monitoring, treatment or alleviation of disease; — diagnosis, monitoring, treatment, alleviation of or compensation for an injury or handicap; — investigation, replacement or modification of the anatomy or of a physiological process; — control of conception; and which does not achieve its principal intended action in or on the human body by pharmacological, immunological or metabolic means, but which may be assisted in its function by such means. 3.7 presterilization count: Viable count obtained prior to sterilization. 3.8 product: Generic term used to describe raw materials, intermediate products, subassemblies and finished medical devices. 3.9 recovery efficiency: Measure of the ability of a specified technique to remove microorganisms from product. 3.10 revalidation: Set of documented procedures to confirm an established validation. 3.11 sample item portion (SIP): Defined p