ASTM D3862-13(2019)

Standard Test Method for Retention Characteristics of 0.2-µm Membrane Filters Used in Routine Filtration Procedures for the Evaluation of Microbiological Water Quality

SIGNIFICANCE AND USE
5.1 Microbiological water testing procedures using membrane filtration are based on the premise that all bacteria within a specific size range will be retained by the membrane filter used. If the membrane filter does not retain these bacteria, false negative results or lowered density estimates may occur that could have serious repercussions due to the presence of unrecognized potential health hazards in the water being tested, especially in drinking water.  
5.1.1 This procedure as devised will enable the user to test each membrane filter lot number for its ability to retain all bacterial equal to, or larger than, the stated membrane pore size.  
5.2 Since this membrane is often used to sterilize nonautoclavable liquids, it is essential that the retention characteristics of this membrane are stable.
SCOPE
1.1 This test method covers a procedure to test membrane filters for their ability to retain bacteria whose diameter is equal to or slightly larger than the 0.2-µm pore size of the membrane filter.  
1.2 The procedures described are for the use of user laboratories as differentiated from manufacturers’ laboratories.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
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: 31-Oct-2019
• ICS: 07.100.20 - Microbiology of water
• Technical Committee: D19 - Water
• Drafting Committee: D19.24 - Water Microbiology

Relations

• Refers: ASTM D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM D1129-10 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2010
• Refers: ASTM D1129-06a - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1129-06ae1 - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1193-06 - Standard Specification for Reagent Water
• Effective Date: 01-Mar-2006
• Refers: ASTM D1129-06 - Standard Terminology Relating to Water
• Effective Date: 15-Feb-2006
• Refers: ASTM D1129-04e1 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-04 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-03a - Standard Terminology Relating to Water
• Effective Date: 10-Aug-2003
• Refers: ASTM D1129-03 - Standard Terminology Relating to Water
• Effective Date: 10-Mar-2003
• Refers: ASTM D1129-02a - Standard Terminology Relating to Water
• Effective Date: 10-Jul-2002
• Refers: ASTM D1129-01 - Standard Terminology Relating to Water
• Effective Date: 10-Jul-2002
• Refers: ASTM D1129-02 - Standard Terminology Relating to Water
• Effective Date: 10-Feb-2002
• Refers: ASTM D1129-99a - Standard Terminology Relating to Water
• Effective Date: 10-Feb-2002
• Refers: ASTM D1193-99 - Standard Specification for Reagent Water
• Effective Date: 10-Feb-1999

Overview

ASTM D3862-13(2019) is the internationally recognized standard test method for evaluating the retention characteristics of 0.2-µm membrane filters used in routine filtration procedures for assessing microbiological water quality. Developed and maintained by ASTM International, this standard is crucial for laboratories performing water quality testing where accurate retention of microorganisms is vital for ensuring safety and regulatory compliance, particularly in drinking water analysis. The procedure enables users to determine if membrane filters consistently retain bacteria equal to or larger than the membrane’s pore size, addressing both public health and laboratory integrity concerns.

Key Topics

• Membrane Filter Retention: The standard outlines a method to verify that 0.2-micrometer membrane filters effectively retain bacteria, minimizing the risk of false negatives and underreporting microbial content.
• Laboratory Validation: ASTM D3862 is designed specifically for user laboratories (distinct from manufacturer settings), ensuring practical relevance in typical water quality testing environments.
• Health and Safety Implications: Accurate filtration is essential; inadequately retaining membranes may allow hazardous bacteria to pass through, compromising water safety and leading to underestimated microbial contamination.
• Testing Procedure: The method is based on filtering a suspension of bacterial cells with diameters close to the 0.2-µm cutoff and then assessing the filtrate for sterility, validating filter performance.
• Equipment and Handling: The standard provides requirements for equipment such as filtration units, vacuum sources, and sterile materials, and stresses the importance of proper membrane handling and apparatus setup to avoid test artifacts.
• Applicability: The procedure applies SI units exclusively and requires users to follow health, safety, and environmental best practices when implementing the method.

Applications

• Drinking Water Testing: Ensures accurate microbial quality analysis, supporting regulatory compliance and safeguarding public health.
• Quality Control in Laboratories: Allows laboratories to verify membrane filter performance on a per-lot basis, ensuring reliability in routine microbial water testing.
• Sterilization of Liquids: Provides confidence in the use of filters for sterilizing liquids that cannot undergo heat sterilization, by validating consistent bacteria retention capabilities.
• Supporting Water Treatment Facilities: Water utilities and treatment plants can use this method to validate their filtration processes and demonstrate compliance with national and international water quality standards.
• Industrial and Research Laboratories: Applicable in settings where precise microbiological filtration is required, such as pharmaceutical, environmental, and research laboratories.

Related Standards

• ASTM D1129: Terminology Relating to Water - provides definitions of terms used in ASTM water-related standards.
• ASTM D1193: Specification for Reagent Water - specifies water quality for laboratory use, including filtration procedures.
• ISO Standards for Membrane Filtration: International standards may complement ASTM D3862 by specifying filtration methods and microbial testing techniques.
• World Trade Organization (WTO) TBT Principles: This standard was developed in accordance with the WTO Technical Barriers to Trade Committee guidelines, ensuring global recognition and harmonization.

Practical Value

Following ASTM D3862-13(2019) helps laboratories and water quality professionals ensure membrane filter performance, verify microbiological water safety, and comply with regulatory requirements. By systematically testing membrane retention characteristics, users can prevent the risk of unrecognized microbial contamination, protect public health, and maintain the integrity of water analysis programs. This standard fosters best practices in laboratory quality assurance, making it an essential document for anyone involved in microbiological water filtration 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: D3862 − 13 (Reapproved 2019)
Standard Test Method for
Retention Characteristics of 0.2-μm Membrane Filters Used
in Routine Filtration Procedures for the Evaluation of
Microbiological Water Quality
This standard is issued under the fixed designation D3862; 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 3.2 Definitions of Terms Specific to This Standard:
3.2.1 Gram’s stain, n—a routine bacterial stain that divides
1.1 This test method covers a procedure to test membrane
bacteria into two categories, depending on whether they can be
filters for their ability to retain bacteria whose diameter is equal
decolorized with acetone, alcohol, or aniline oil after staining
to or slightly larger than the 0.2-μm pore size of the membrane
with one of the rosaniline dyes such as crystal violet, methyl
filter.
violet, or gentian violet and treating with iodine. Those that
1.2 The procedures described are for the use of user
resist decolorization remain blue or violet and are designated
laboratories as differentiated from manufacturers’ laboratories.
Gram-positive; those that are decolorized and take up the red
1.3 The values stated in SI units are to be regarded as counterstain, such as neutral red, safranin, or dilute carbol
standard. No other units of measurement are included in this fuchsin are termed Gram-negative.
standard.
3.2.2 vacuum, n—for the procedure used, source of suction
1.4 This standard does not purport to address all of the that can produce a reading of 500 to 600 mm Hg on a vacuum
safety concerns, if any, associated with its use. It is the gage.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
4. Summary of Test Method
mine the applicability of regulatory limitations prior to use.
4.1 This test method is based on the cultivation of organ-
1.5 This international standard was developed in accor-
isms whose diameters are equal to or slightly larger than pores
dance with internationally recognized principles on standard-
of the membrane filter to be tested and then filtering a specific
ization established in the Decision on Principles for the
aliquot containing organisms through the membrane followed
Development of International Standards, Guides and Recom-
by an examination of the filtrate after incubation for sterility. A
mendations issued by the World Trade Organization Technical
sterile filtrate indicates complete retention of the organism and
Barriers to Trade (TBT) Committee.
validates the ability of the membrane to retain bacteria equal to
or slightly larger than the stated pore size.
2. Referenced Documents
2.1 ASTM Standards:
5. Significance and Use
D1129 Terminology Relating to Water
5.1 Microbiological water testing procedures using mem-
D1193 Specification for Reagent Water
brane filtration are based on the premise that all bacteria within
a specific size range will be retained by the membrane filter
3. Terminology
used. If the membrane filter does not retain these bacteria, false
3.1 Definitions:
negative results or lowered density estimates may occur that
3.1.1 For definitions of terms used in this standard, refer to
could have serious repercussions due to the presence of
Terminology D1129.
unrecognized potential health hazards in the water being tested,
especially in drinking water.
5.1.1 This procedure as devised will enable the user to test
This test method is under the jurisdiction of ASTM Committee D19 on Water
and is the direct responsibility of Subcommittee D19.24 on Water Microbiology.
each membrane filter lot number for its ability to retain all
Current edition approved Nov. 1, 2019. Published December 2019. Originally
bacterial equal to, or larger than, the stated membrane pore
approved in 1990. Last previous edition approved in 2013 as D3862 – 13. DOI:
size.
10.1520/D3862-13R19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.2 Since this membrane is often used to sterilize nonauto-
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
clavable liquids, it is essential that the retention characteristics
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. of this membrane are stable.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3862 − 13 (2019)
6. Apparatus where such specifications are available. Other grades may be
used, provided it is first ascertained that the reagent is of
6.1 Membrane Filtration Units, six.
sufficiently high purity to permit its use without lessening the
6.2 Vacuum Source, with trap vessel. accuracy of the determination.
7.2 Purity of Water—Unless otherwise indicated, reference
6.3 Filtering flasks, 1-L, with vacuum tubing into which a
to water shall be understood to mean reagent water conforming
glass tube and a Y-tube have been incorporated as in Fig. 1. The
to Specification D1193, Type II, for 0.2-μm membrane filtra-
free end of the Y-tube is connected by tubing to a sterile
tion. In addition, suitability tests for determining the bacteri-
bacterial air vent. The tubing to air vent is clamped shut during
cidal properties of the reagent grade water should be per-
filtration and released after filtration.
formed.
6.4 Forceps, blunt-nosed, and small beaker of 95 % ethanol.
7.3 Bacterial Suspension —Prepare 100 mL of a suspension
6.5 Incubator, 37°C.
of a Pseudomonas diminuta (ATCC 19146). Add 1.0 mL of a
24 6 2 h saline lactose broth culture to 99 mL of 0.1 % peptone
6.6 Pinch-Cock Clamps.
water. This suspension will contain approximately 106 to 107
6.7 Autoclave or Other Sterilizing Equipment.
organisms per millilitre.
6.8 Appropriate Equipment for producing reagent grade
7.4 Peptone Water (0.1 %)—Prepare a 10 % stock solution
waters. of peptone in water. Dilute a measured volume of the 10 %
stock solution to obtain final solution of 0.1 % peptone in
6.9 Appropriate Laboratory Glassware.
required amount. Sterilize at 121°C for 15 min.
6.10 Sterile Rubber Stoppers, to fit 1-L filtering flask.
7.5 Test Organism—Pseudomonas diminuta ATCC strain
6.11 Expendables: 19146, also called FDA strain PC1—818.
6.11.1 Double-Strength Broth, 140-mL aliquots.
7.6 Tryptic Soy Agar and Tryptone Soya Agar are inter-
6.11.2 Sterile Pipets, 1 and 10-mL.
changeable and henceforth referred to as
...