ASTM F838-20

Standard Test Method for Determining Bacterial Retention of Membrane Filters Utilized for Liquid Filtration

SIGNIFICANCE AND USE
5.1 This test method is designed to assess the retentivity of a sterilizing filter under standard challenge conditions.  
5.1.1 A challenge of 107 bacteria per cm2 of effective filtration area is selected to provide a high degree of assurance that the method has sufficient sensitivity to detect oversized pores and that the filter will quantitatively retain large numbers of organisms. The model challenge organism, B. diminuta, is widely considered to be a small bacterium and is recognized as an industry standard for qualifying sterilizing filters. Other species may represent a worst-case test in terms of ability to penetrate a filter. This test does not provide assurance that filters can completely retain such bacteria.  
5.1.2 The analytical procedure utilized in this test method provides a method to assign a numerical value to the filtration efficiency of the filter being evaluated under standard filtration conditions. For the purpose of product sterility assurance, additional process-specific studies should be performed.
SCOPE
1.1 This test method determines the bacterial retention characteristics of membrane filters for liquid filtration using Brevundimonas diminuta as the challenge organism. This test method can be used to evaluate any membrane filter system used for liquid sterilization.  
1.2 This test method is not intended to be used in performance of product- and process-specific validation of the bacterial retention characteristics of membrane filters to be used in pharmaceutical or biopharmaceutical sterilizing filtration, or both. Process- and product-specific bacterial retention validation should be carried out using the intended product manufacturing process parameters and the product solution or surrogate as the carrier fluid.  
1.3 The values stated in SI units are to be regarded as standard.  
1.3.1 Exception—The inch-pound values given for units of pressure are to be regarded as standard; SI unit conversions are shown in parentheses.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2020
• ICS: 07.100.20 - Microbiology of water
• Technical Committee: E55 - Manufacture of Pharmaceutical and Biopharmaceutical Products
• Drafting Committee: E55.14 - Measurement Systems and Analysis

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F838 − 20
Standard Test Method for
Determining Bacterial Retention of Membrane Filters
1
Utilized for Liquid Filtration
This standard is issued under the fixed designation F838; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2
1.1 This test method determines the bacterial retention 2.1 ASTM Standards:
characteristics of membrane filters for liquid filtration using D1193 Specification for Reagent Water
Brevundimonas diminuta as the challenge organism. This test
3. Terminology
method can be used to evaluate any membrane filter system
used for liquid sterilization.
3.1 Definitions:
3.1.1 log reduction value, n—the logarithm to the base 10 of
1.2 This test method is not intended to be used in perfor-
the ratio of the number of microorganisms in the challenge to
mance of product- and process-specific validation of the
the number of organisms in the filtrate.
bacterial retention characteristics of membrane filters to be
used in pharmaceutical or biopharmaceutical sterilizing
4. Summary of Test Method
filtration, or both. Process- and product-specific bacterial
4.1 After sterilization, the test filter is challenged with a
retention validation should be carried out using the intended
3 7
suspension of B. diminuta (ATCC 19146 ) to provide 10
product manufacturing process parameters and the product
2
organisms per cm of effective filtration area (EFA) at a
solution or surrogate as the carrier fluid.
maximum differential pressure across the test filter of 30 psig
1.3 The values stated in SI units are to be regarded as –3
(206 kPa) and a flux of 2 to 4 × 10 L per min (3.3 to 6.7 ×
standard. –8 3 2
10 m /s) per cm of effective filtration area. The entire filtrate
1.3.1 Exception—The inch-pound values given for units of
is passed through an analytical membrane filter disc, which is
pressure are to be regarded as standard; SI unit conversions are
subsequently incubated on a solidified growth medium. Micro-
shown in parentheses.
organisms that are not retained by the filter being tested will
1.4 This standard does not purport to address all of the
develop into visible colonies on the analysis membrane and can
safety concerns, if any, associated with its use. It is the
then be enumerated.
responsibility of the user of this standard to establish appro-
5. Significance and Use
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
5.1 This test method is designed to assess the retentivity of
1.5 This international standard was developed in accor-
a sterilizing filter under standard challenge conditions.
7 2
dance with internationally recognized principles on standard-
5.1.1 A challenge of 10 bacteria per cm of effective
ization established in the Decision on Principles for the
filtration area is selected to provide a high degree of assurance
Development of International Standards, Guides and Recom-
that the method has sufficient sensitivity to detect oversized
mendations issued by the World Trade Organization Technical
pores and that the filter will quantitatively retain large numbers
Barriers to Trade (TBT) Committee.
of organisms. The model challenge organism, B. diminuta, is
1 2
This test method is under the jurisdiction of ASTM Committee E55 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Manufacture of Pharmaceutical and Biopharmaceutical Products and is the direct contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
responsibility of Subcommittee E55.14 on Measurement Systems and Analysis. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Oct. 1, 2020. Published October 2020. Originally the ASTM website.
ɛ1 3
approved in 1983. Last previous edition published in 2015 as F838 – 15a . DOI: Available from American Type Culture Collection (ATCC), 10801 University
10.1520/F0838-20. Boulevard, Manassas, VA 20110, http://www.atcc.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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F838 − 20
widely considered to be a small bacterium and is recognized as the specifications of the American Chemical Society, where
4
an industry standard for qualifying sterilizing filters. Other such specifications are available.
species may represent a worst-case test i
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: F838 − 15a F838 − 20
Standard Test Method for
Determining Bacterial Retention of Membrane Filters
1
Utilized for Liquid Filtration
This standard is issued under the fixed designation F838; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
NOTE—Fig. 1 was editorially updated and the year date changed on Sept. 30, 2015.
1
ε NOTE—9.1 was editorially corrected in August 2018.
1. Scope
1.1 This test method determines the bacterial retention characteristics of membrane filters for liquid filtration using Brevundi-
monas diminuta as the challenge organism. This test method maycan be employedused to evaluate any membrane filter system
used for liquid sterilization.
1.2 This test method is not intended to be used in performance of product- and process-specific validation of the bacterial retention
characteristics of membrane filters to be used in pharmaceutical or biopharmaceutical sterilizing filtration, or both. Process- and
product-specific bacterial retention validation should be carried out using the intended product manufacturing process parameters
and the product solution or surrogate as the carrier fluid.
1.3 The values stated in SI units are to be regarded as standard.
1.3.1 Exception—The inch-pound values given for units of pressure are to be regarded as standard; SI unit conversions are shown
in parentheses.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
D1193 Specification for Reagent Water
3. Terminology
3.1 Definitions:
1
This test method is under the jurisdiction of ASTM Committee E55 on Manufacture of Pharmaceutical and Biopharmaceutical Products and is the direct responsibility
of Subcommittee E55.03 on General Pharmaceutical Standards.
Current edition approved Sept. 30, 2015Oct. 1, 2020. Published October 2015October 2020. Originally approved in 1983. Last previous edition published in 2015 as
ɛ1
F838 – 15.F838 – 15a . DOI: 10.1520/F0838-15AE01.10.1520/F0838-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
F838 − 20
3.1.1 log reduction value—value, n—the logarithm to the base 10 of the ratio of the number of microorganisms in the challenge
to the number of organisms in the filtrate.
4. Summary of Test Method
3
4.1 After sterilization, the test filter is challenged with a suspension of B. diminuta (ATCC 19146 ) at a concentration of to provide
7 2
10 organisms per cm of effective filtration area (EFA) at a maximum differential pressure across the test filter of 30 psig (206
–3 –8 3 2
kPa) and a flow rate flux of 2 to 4 × 10 LPM per L per min (3.3 to 6.7 × 10 m /s) per cm of effective filtration area. The entire
filtrate is then filtered passed through an analytical membrane filerfilter disc, which is subsequently incubated on a solidified growth
medium. Microorganisms that are not retained by the filter being tested will develop into visible colonies on the analysis membrane
and can then be enumerated.
5. Significance and Use
5.1 This test method is designed to assess the retentivity of a sterilizing filter under standard challenge conditions.
7 2
5.1.1 A challenge of 10 bacteria per cm of effective filtration area is selected to provide a high degree of assurance that the filter
will be challenged uniformly across the membrane surface to assure itmethod has sufficient sensitivity to detect oversized pores
and that the filter will quantita
...