ASTM D4196-82(1998)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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An American National Standard
Designation: D 4196 – 82 (Reapproved 1998)
Standard Test Method for
Confirming the Sterility of Membrane Filters
This standard is issued under the fixed designation D 4196; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 6. Reagents and Materials
1.1 This test method describes a test to confirm the sterility 6.1 Purity of Water— Unless otherwise indicated, reference
of either manufacturer presterilized or user-sterilized analytical to water shall be understood to mean Type II reagent grade
membrane filters. water in accordance with Specification D 1193.
1.2 This standard does not purport to address all of the 6.2 Media—Use commercially available dehydrated media.
safety concerns, if any, associated with its use. It is the Dissolve and sterilize by autoclaving, in accordance with the
responsibility of the user of this standard to establish appro- manufacturer’s directions.
priate safety and health practices and determine the applica- 6.2.1 Fluid Thioglycollate Medium (Note)—Dispense
bility of regulatory limitations prior to use. 40-mL aliquots into suitable-sized vessels with screw-cap
closure,providingaratioofsurfaceareatodepthofmediumso
2. Referenced Documents
that no more than the upper half of the medium has initially
2.1 ASTM Standards: undergone a color change indicative of oxygen uptake. When
D 1129 Terminology Relating to Water
ready for use, not more than the upper one tenth of the medium
D 1193 Specification for Reagent Water should be pink. The medium may be restored once by heating
2.2 Other Standard:
infree-flowingsteamuntilthepinkcolordisappears.ThepHof
The United States Pharmacopeia, Current Edition (Sec- the medium, after autoclaving, should be 7.1 6 0.2.
tions on Sterilization and Sterility Testing)
NOTE 1—If stored at 2 to 5°C in sealed containers, the media may be
used for 1 year provided they are tested for the growth-promoting
3. Terminology
properties every 3 months.
3.1 Definitions—For definitions of terms used in this test
6.2.2 Soybean-Casein Digest Medium (Note)—Dispense
method, refer to Terminology D 1129.
40-mL aliquots into suitable vessels with screw-cap closure.
The pH after autoclaving should be 7.3 6 0.2.
4. Summary of Test Method
6.2.3 Perform a sterility test on each lot of autoclaved
4.1 The membrane filters are immersed in sterile culture
medium by incubating ten representative containers of each
media and incubated at temperatures that are suitable for
medium, for not less than 10 days, at the specified test
growth of viable bacteria, fungi, and yeasts. Growth of
temperature.
organisms is evidence that the filter has failed the test.
6.2.4 Perform a growth-promotion test, as described below,
on each lot of autoclaved medium.
5. Significance and Use
6.2.4.1 Inoculate duplicate test containers of each medium
5.1 This test method may be employed to check the sterility
separately with less than 100 of each of the below listed
of commercially procured sterile membrane filters. The test
microorganisms. Incubate 7 days at the temperatures listed
also confirms that sterilized filters have not been contaminated.
below:
Additionally, this test may be used to monitor the efficacy of
in-house sterilization procedures. Filter packages that have
A
Medium Test Organisms Temperature,° C
B
obvious packaging defects should not be tested because steril-
Fluid thioglycollate Bacillus subtilis (ATCC 6633) 30 to 35
Candida Albicans (ATCC 10231) 30 to 35
ity may have been compromised.
B
Soybean-casein Bacillus subtilis (ATCC 6633) 20 to 25
Candida albicans (ATCC 10231) 20 to 25
A
1 Available from the American Type Culture Collection, 12301 Parkview Drive,
This test method is under the jurisdiction ofASTM Committee D-19 on Water
Rockville, MD 20852.
and is the direct responsibility of Subcommittee D19.08 on Membranes and Ion
B
If a non-spore-forming organism is desired, use Micrococcus Luteus (ATCC
Exchange Materials.
9341).
Current edition approved Oct. 29, 1982. Published Marc
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