ASTM E2471-05(2011)e1
(Test Method)Standard Test Method for Using Seeded-Agar for the Screening Assessment of Antimicrobial Activity In Carpets
Standard Test Method for Using Seeded-Agar for the Screening Assessment of Antimicrobial Activity In Carpets
SIGNIFICANCE AND USE
This test method provides for rapid screening of antimicrobial treatments located in or on the carpet face fiber or incorporated into the backing structure of the carpet (or both).
This test method simulates actual use conditions that may occur on carpets (for example, food and beverage spills, soiling from foot traffic, prolonged moisture exposure).
This test method provides a means to screen for activity and durability of an antimicrobial treatment under conditions of organic loading.
This test method provides for the simultaneous assessment of multiple carpet components for antimicrobial activity.
Carpets may be cleaned prior to testing with this test method in order to assess the durability of the antimicrobial effect.
SCOPE
1.1 This test method is designed to evaluate (qualitatively) the presence of antimicrobial activity in or on carpets. Use this test method to qualitatively evaluate both antibacterial and antifungal activity.
1.2 Use half strength (nutrient and agar) tryptic soy agar as the inoculum vehicle for bacteria and half strength potato dextrose agar as the inoculum vehicle for mold conidia. Use of half strength agars may reduce undue neutralization of an antimicrobial due to excessive organic load.
1.3 This test method simultaneously evaluates (both visual and stereo-microscopic) antimicrobial activity both at the fiber layer and at the primary backing layer of carpet.
1.4 Use this test method to assess the durability of the antimicrobial treatments on new carpets, and on those repeatedly shampooed or exposed to in-use conditions.
1.5 Knowledge of microbiological techniques is required for the practice of this test method.
1.6 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E2471 − 05 (Reapproved 2011)
Standard Test Method for
Using Seeded-Agar for the Screening Assessment of
Antimicrobial Activity In Carpets
This standard is issued under the fixed designation E2471; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
´ NOTE—Editorial changes were made throughout in April 2011.
INTRODUCTION
Today’smoderncommercialcarpets(especiallymodularcarpettile)oftenincorporateantimicrobial
agents either in or on the face fibers or incorporated into the primary backing (attachment point of
carpet fiber to the backing structure). The American Association of Textile Chemists and Colorists
(AATCC) Method 174 permits both qualitative and quantitative antibacterial assessment and
antifungal assessment (qualitative only) of antimicrobial treatments in or on carpet. However, the
method is not suited for rapid screening of antimicrobials low in water solubility or that have slow
diffusion rates when incorporated into the carpet’s primary backing layer. The test method described
here provides a rapid screen of antimicrobial activity in or on carpets and allows for the simultaneous
assessment of multiple components of the carpet (not just the fibers).
1. Scope priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1 This test method is designed to evaluate (qualitatively)
the presence of antimicrobial activity in or on carpets. Use this
2. Referenced Documents
test method to qualitatively evaluate both antibacterial and
2.1 American Association of Textile Chemists and Colorists
antifungal activity.
(AATCC) Standard:
1.2 Use half strength (nutrient and agar) tryptic soy agar as
Method 174-2007,Antimicrobial Activity Assessment of
the inoculum vehicle for bacteria and half strength potato 2
Carpets
dextroseagarastheinoculumvehicleformoldconidia.Useof
half strength agars may reduce undue neutralization of an 3. Terminology
antimicrobial due to excessive organic load.
3.1 Definitions:
1.3 This test method simultaneously evaluates (both visual 3.1.1 face fiber, n—the wear layer of the carpet; can be
and stereo-microscopic) antimicrobial activity both at the fiber
composed of nylon, polypropylene, wool, or other natural or
layer and at the primary backing layer of carpet. synthetic polymers. Typically, face fiber is tufted into a woven
ornon-wovenscrimandthencoatedwithlatextobondtheface
1.4 Use this test method to assess the durability of the
fiber securely to the backing; this latex coated scrim forms the
antimicrobial treatments on new carpets, and on those repeat-
primary backing.
edly shampooed or exposed to in-use conditions.
3.1.2 inoculum vehicle, n—carrier solution used to transport
1.5 Knowledge of microbiological techniques is required
bacterial cells or mold conidia to the test substrate.
for the practice of this test method.
3.1.3 primary backing, n—the uppermost layer of carpet
1.6 This standard does not purport to address all of the
backing where carpet fiber bundles are physically attached at
safety concerns, if any, associated with its use. It is the
the base to the backing structure. This layer is typically
responsibility of the user of this standard to establish appro-
constructed of synthetic latex (ethylene vinyl acetate, styrene
butadiene, or a thermo-polymer; that is, ethylene vinyl acetate
hot-melt adhesive).
This test method is under the jurisdiction of ASTM Committee E35 on
Pesticides, Antimicrobials, and Alternative Control Methods and is the direct
responsibility of Subcommittee E35.15 on Antimicrobial Agents. Available from American Association of Textile Chemists and Colorists
Current edition approved March 1, 2011. Published April 2011. Originally (AATCC), P.O. Box 12215, Research Triangle Park, NC 27709, http://
approved in 2005 as E2471–05. DOI: 10.1520/E2471-05R11E01. www.aatcc.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E2471 − 05 (2011)
3.1.4 seeded agar, n—a thin layer of molten (liquid) micro- 6.11 Test Carpet.
biologicalagarcontainingeitherbacterialcellsormoldconidia
6.12 Electric Hair Clippers (Oster GoldenA5 or equivalent
(spores) used to challenge a test substrate.
#30 Blade).
4. Summary of Test Method 6.13 Canned Air (compressed air for surface dusting).
6.14 Sterile Petri Dishes, 100 mm.
4.1 Cut carpet samples into small rectangular pieces either
via a carpet knife or mechanical die and press. Shave half of
6.15 Carpet Knife (razor knife).
the face fiber on each sample using electric hair clippers and
6.16 Mechanical Die (Optional), 2.5 by 3.8 cm.
arrange in sterile Petri dishes (typically with the shaven half of
thesamplefacingthecenterofthedish.Coolmoltenagars(full 6.17 Hydraulic Press (Optional).
or partial complement) to 45 6 2°C and inoculate with the
6.18 Sterile Funnel, with a glass wool plug.
challenge bacteria or mold conidia. Following wrist action
6.19 Counting Chamber (hemocytometer).
mixing, immerse samples into the seeded-molten agar, place
into a Petri dish and pour additional seeded agar into the dish 6.20 Light Microscope, 10 and 40× objectives.
to surround but not cover the test sample. Incubate the Petri
6.21 Disposable Examination Gloves.
dish for 24 to 72 h at 30 6 2°C. Visually and microscopically
examine both at the face fiber and shaven (primary backing)
7. Reagents
layer for inhibition of the challenge microorganisms. Report
7.1 Media:
thepresenceofcarpetsurfaceinhibition(forlowwatersoluble
7.1.1 Tryptic Soy Broth.
or slow migrating antimicrobials) or zone of inhibition for
7.1.2 Tryptic Soy Agar.
water soluble antimicrobials.
7.1.3 Potato Dextrose Agar.
7.1.4 Sterile 0.85 % Saline, with 0.1% polysorbate 80.
5. Significance and Use
7.2 Test Organisms—Specific organisms are recommended;
5.1 This test method provides for rapid screening of anti-
however, other microorganisms may be used to mimic those
microbial treatments located in or on the carpet face fiber or
found in a specific environment or those expected contami-
incorporated into the backing structure of the carpet (or both).
nants which may be present where the carpet is expected to
5.2 This test method simulates actual use conditions that
perform.
may occur on carpets (for example, food and beverage spills,
7.2.1 Gram-positive bacteria Staphylococcus aureus ATCC
soiling from foot traffic, prolonged moisture exposure).
6538.
5.3 This test method provides a means to screen for activity
7.2.2 Gram-negative bacteria Serratia marcescens ATCC
and durability of an antimicrobial tre
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