ASTM D2574-16(2020)e1
(Test Method)Standard Test Method for Resistance of Emulsion Paints in the Container to Attack by Microorganisms
Standard Test Method for Resistance of Emulsion Paints in the Container to Attack by Microorganisms
SIGNIFICANCE AND USE
4.1 Spoilage of paint in the container can result in putrefaction, lowered pH, gas formation, and decrease in viscosity. This test method provides a standard procedure for the evaluation of the resistance of emulsion paints to microbial deterioration. The results should enable: (1) the paint manufacturer to select an effective preservative and (2) the supplier of preservatives to evaluate the performance in emulsion paints of competitive and developmental preservatives.
4.2 This test method should be used preferably by persons who have had basic microbiological training.
Note 1: The reliability of the results obtained from this test method is extremely dependent on the techniques employed. Improper techniques can result in a sterile sample appearing to be contaminated, and even worse, a contaminated sample appearing to be sterile (see also Note 2). It is recommended that you consult with your biocide supplier, raw material supplier, or an independent testing laboratory to confirm questionable results. Formulation and raw materials’ quality may also vary and thereby affect the test results.
SCOPE
1.1 This test method covers the determination of the relative resistance of emulsion paints to attack in the container by microorganisms.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 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.
1.4 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
Relations
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.
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Designation: D2574 − 16 (Reapproved 2020)
Standard Test Method for
Resistance of Emulsion Paints in the Container to Attack by
Microorganisms
This standard is issued under the fixed designation D2574; 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.
ε NOTE—Editorial changes were made in subsections 5.16, 6.3, and 7.3.2 in August 2020.
1. Scope 4. Significance and Use
1.1 This test method covers the determination of the relative
4.1 Spoilage of paint in the container can result in
resistance of emulsion paints to attack in the container by
putrefaction, lowered pH, gas formation, and decrease in
microorganisms.
viscosity. This test method provides a standard procedure for
the evaluation of the resistance of emulsion paints to microbial
1.2 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information deterioration. The results should enable: (1) the paint manu-
only. facturer to select an effective preservative and (2) the supplier
ofpreservativestoevaluatetheperformanceinemulsionpaints
1.3 This standard does not purport to address all of the
of competitive and developmental preservatives.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4.2 This test method should be used preferably by persons
priate safety, health, and environmental practices and deter-
who have had basic microbiological training.
mine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accor- NOTE 1—The reliability of the results obtained from this test method is
extremely dependent on the techniques employed. Improper techniques
dance with internationally recognized principles on standard-
can result in a sterile sample appearing to be contaminated, and even
ization established in the Decision on Principles for the
worse, a contaminated sample appearing to be sterile (see also Note 2). It
Development of International Standards, Guides and Recom-
is recommended that you consult with your biocide supplier, raw material
mendations issued by the World Trade Organization Technical
supplier, or an independent testing laboratory to confirm questionable
Barriers to Trade (TBT) Committee.
results. Formulation and raw materials’quality may also vary and thereby
affect the test results.
2. Referenced Documents
2 5. Apparatus and Materials
2.1 ASTM Standards:
D5588 Test Method for Determination of the Microbial
5.1 Balance, capable of weighing to 0.10 g.
Condition of Paint, Paint Raw Materials, and Plant Areas
5.2 Incubator, or other device capable of maintaining a
constant temperature between 28 and 32°C.
3. Summary of Test Method
3.1 Thistestmethodisdesignedtochallengesamplesofone 5.3 Refrigerator, maintained at 10 to 13°C.
or more paints containing various levels of one or more
5.4 Screwcap Borosilicate Test Tubes, 125 by 15-mm.
biocides with a known amount of bacteria and rate the ability
of the test paint(s) to control the “contamination.”
5.5 Borosilicate Flasks, 1-L.
5.6 Screwcap Bottles, 150-mL.
1 5.7 Autoclave, capable of producing 103 kPa (15 psi) of
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
steam pressure at 121°C and maintaining it for a minimum of
Subcommittee D01.28 on Biodeterioration.
15 min. An autoclave is not necessary if prepared agar slants
Current edition approved Aug. 1, 2020. Published August 2020. Originally
are used.
approved in 1967. Last previous edition approved in 2016 as D2574 – 16. DOI:
10.1520/D2574-16R20E01.
2 5.8 Pipettes or an Automatic Pipettor, sterile, 1-mL, with
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM sterile disposable pipette tips for 1 mL.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 5.9 Petri Dishes, sterile.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D2574 − 16 (2020)
5.10 Dehydrated Tryptic Soy Agar (TSA), medium, or pre- 6.2.4 Upon removal from the autoclave, allow the tubes to
prepared slants, plates, and broth tubes. cool to room temperature, tighten the caps, and store until
needed.
5.11 Swabs, sterile cotton.
6.3 Inoculation of Tryptic Soy Broth Tubes with the
5.12 Laminar Flow Hood, Sterile Room, or at Least a
Pseudomonas sp. and the Klebsiella sp:
Laboratory TestingArea, relatively clean, free of blowing dust
6.3.1 Above organisms are stored on tryptic soy agar slants
and dirt, etc., which can be used for streaking plates.
in a refrigerator.To prepare a 24-h culture of each of the above
5.13 Antiseptic Solution, to help maintain sterility of testing
organisms, the surface of a slant of each organism is scraped
area surfaces (4.12) (for example, 70 % ethanol solution).
off with a sterile inoculating loop. This material is inoculated
5.14 A minimum of 235 mL ( ⁄2 pt) of each paint sample
into a tube ofTSB each and incubated in a 30 6 2°C incubator
under test (pre-loaded with biocide). overnight.
6.3.2 The overnight cultures are used to reinoculate fresh
5.15 Aminimum of 475 mL(1 pt) of paint identical to 5.14,
TSB tubes using a sterile inoculating loop.
but containing no biocide.
6.3.3 Incubate the cultures to their log phase of growth as
5.16 Twenty-four Hour Cultures of a Pseudomonas sp. (for
previously determined by standard microbiological technique
example, Pseudomonas aeruginosa ATCC #10145) and an
and growth curves using a plate count usually 16 to 24 h.
Klebsiella sp. (for example, Klebsiella aerogenes, ATCC
6.3.4 Soak a sterile cotton swab or a loop in the inoculated
#13048)—These should be grown separately in tryptic soy
broth culture following the incubation period described in
broth. If a spoiled paint of a similar type as that under test is
6.3.3.
available, organisms cultured from this material can be used.
6.3.5 Remove the swab or loop and prepare a second broth
NOTE 2—See for a method to spoil paint for use as an inoculum.
culture by repeating 6.3.2 and 6.3.3.
Organisms isolated following the procedures in Test Method D5588 may
6.3.6 Following the incubation period, use the broth culture
be used as challenge organisms in Test Method D2574. Also Bacillus sp.
prepared in 6.3.5 to proceed as in Section 7 to inoculate the
for example,Bacillussubtilis,ATCC #27328 or other organisms as agreed
paint.
upon between the parties involved may be employed. When using
spore-forming bacteria, care must be taken to ensure only vegetative cells
NOTE 4—Maintenance of cultures for future use: The purity of the
are used in the inoculation (early log phase of growth).
bacterialinoculumpreparedin6.3.2isverifiedbystreakingaloopfulfrom
the growth onto a prepared TSA plate. A single isolated colony from the
6. Preparation of Materials
plate is then transferred to a previously prepared TSA slant using an
NOTE 3—Observe conventional microbiological techniques in making
inoculating loop. Incubate the slant for 24 h at 30 6 2°C or until a
these tests. Handle all materials so as to avoid contamination from the air,
luxuriant growth occurs on the slant surface.The slant is then stored in the
fingers, or work surfaces.
refrigerator as a working stock culture until further use.
6.1 Preparation of Tryptic Soy Agar Plates and Slants: NOTE 5—The inoculum preparation for Bacillus substilis differs from
the other cultures. Bacillus subtilis, ATCC 27328 has been shown to
6.1.1 Follow the instructions on the container for
produce extracellular cellulase enzymes in the TSB medium. Hence, it is
preparation, or purchase prepared plates and slants.
advised that for Bacillus inoculum, the broth culture from 6.3.5 should be
6.1.2 Distribute10mLofthedissolvedmediumintoeachof
centrifuged at 4000 r/m for 10 min, the supernatant containing the
50 test tubes and 100-mL medium in 250-mL conical flasks.
cellulase enzymes is discarded and the bacterial pellet is re-suspended in
6.1.3 Autoclave tubes (with caps loose) and the flask for 15 equal volume of sterile water and then used as the inoculum in Section 7.
min at 103 kPa (15 psi) and a temperature of 121°C.
6.4 Preparation of Paints for Test:
6.1.4 Upon removal from the autoclave, tighten caps and
6.4.1 Paints may be previously loaded with biocide as
place the tubes at an approximate 30° angle position to prepare
provided, or ladders of levels of biocide may be added as
the slants with a slope of about 50 mm (2 in.) long.
agreed upon by the parties involved. In all testing, a negative
6.1.5 For preparing TSA plates, pour 30 mL of the agar
control (sample containing no biocide) should be included and
medium from the flask into sterile petri dishes and allow to set.
appropriatelyidentified.Ifanuntreatedcontrolisnotavailable,
6.1.6 Store the prepared TSA slants and plates in a refrig-
confirm viability of each culture by streaking the broth onto a
erator at 10 to 13°C until needed.
fresh TSA plate.
6.2 Preparation of Tryptic Soy Broth Tubes (TSB): 6.4.2 Weigh 100 g of each paint sample to be tested into a
6.2.1 Follow the instructions on the container for
suitable container (screwcap glass jars have been found suit-
preparat
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