ASTM_E_2471_-_05_2016.pdf

Designation:E247105(Reapproved 2016)Standard Test Method forUsing Seeded-Agar for the Screening Assessment ofAntimicrobial Activity In Carpets1This standard is issued under the fixed designation E2471;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONTodays modern commercial carpets(especially modular carpet tile)often incorporate antimicrobialagents either in or on the face fibers or incorporated into the primary backing(attachment point ofcarpet fiber to the backing structure).The American Association of Textile Chemists and Colorists(AATCC)Method 174 permits both qualitative and quantitative antibacterial assessment andantifungal assessment(qualitative only)of antimicrobial treatments in or on carpet.However,themethod is not suited for rapid screening of antimicrobials low in water solubility or that have slowdiffusion rates when incorporated into the carpets primary backing layer.The test method describedhere provides a rapid screen of antimicrobial activity in or on carpets and allows for the simultaneousassessment of multiple components of the carpet(not just the fibers).1.Scope1.1 This test method is designed to evaluate(qualitatively)the presence of antimicrobial activity in or on carpets.Use thistest method to qualitatively evaluate both antibacterial andantifungal activity.1.2 Use half strength(nutrient and agar)tryptic soy agar asthe inoculum vehicle for bacteria and half strength potatodextrose agar as the inoculum vehicle for mold conidia.Use ofhalf strength agars may reduce undue neutralization of anantimicrobial due to excessive organic load.1.3 This test method simultaneously evaluates(both visualand stereo-microscopic)antimicrobial activity both at the fiberlayer and at the primary backing layer of carpet.1.4 Use this test method to assess the durability of theantimicrobial treatments on new carpets,and on those repeat-edly shampooed or exposed to in-use conditions.1.5 Knowledge of microbiological techniques is requiredfor the practice of this test method.1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 American Association of Textile Chemists and Colorists(AATCC)Standard:Method 174-2007,Antimicrobial Activity Assessment ofCarpets23.Terminology3.1 Definitions:3.1.1 face fiber,nthe wear layer of the carpet;can becomposed of nylon,polypropylene,wool,or other natural orsynthetic polymers.Typically,face fiber is tufted into a wovenor non-woven scrim and then coated with latex to bond the facefiber securely to the backing;this latex coated scrim forms theprimary backing.3.1.2 inoculum vehicle,ncarrier solution used to transportbacterial cells or mold conidia to the test substrate.3.1.3 primary backing,nthe uppermost layer of carpetbacking where carpet fiber bundles are physically attached atthe base to the backing structure.This layer is typicallyconstructed of synthetic latex(ethylene vinyl acetate,styrenebutadiene,or a thermo-polymer;that is,ethylene vinyl acetatehot-melt adhesive).3.1.4 seeded agar,na thin layer of molten(liquid)micro-biological agar containing either bacterial cells or mold conidia(spores)used to challenge a test substrate.1This test method is under the jurisdiction of ASTM Committee E35 onPesticides,Antimicrobials,and Alternative Control Agents and is the directresponsibility of Subcommittee E35.15 on Antimicrobial Agents.Current edition approved Nov.1,2016.Published December 2016.Originallyapproved in 2005 as E2471 05.Last previous edition published in 2011 asE247105(2011)1.DOI:10.1520/E2471-05R16.2Available from American Association of Textile Chemists and Colorists(AATCC),P.O.Box 12215,Research Triangle Park,NC 27709-2215,http:/www.aatcc.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.Summary of Test Method4.1 Cut carpet samples into small rectangular pieces eithervia a carpet knife or mechanical die and press.Shave half ofthe face fiber on each sample using electric hair clippers andarrange in sterile Petri dishes(typically with the shaven half ofthe sample facing the center of the dish.Cool molten agars(fullor partial complement)to 45 6 2C and inoculate with thechallenge bacteria or mold conidia.Following wrist actionmixing,immerse samples into the seeded-molten agar,placeinto a Petri dish and pour additional seeded agar into the dishto surround but not cover the test sample.Incubate the Petridish for 24 to 72 h at 30 6 2C.Visually and microscopicallyexamine both at the face fiber and shaven(primar