AATCC 174-1998 Antimicrobial Activity Assessment of Carpets

AATCC 174-1998 Antimicrobial Activity Assessment of Carpets. 10. Test Specimens 10.1 Test specimcns. (non-sterile) are cul by hand or with a die. They may be any convenient size although oblong spec- imens cut 25 x 50 mm are recomencied. 10.2 If possible. test a specimen of the same material treatcd in exactly the same way with whatever other finishing agents were used. but without the antibacterial agent. Hlowever, this is not essential for the validily of the test. Many standard fin- ishing chemicals will give strong antibac- tcrial activily cven afier many clcanings. 11. Procedure 11.1 If durability data are desired. car- pet spccimens must be tested before and after being cleaned by a cst method agreed upon by the intcrested parties. 11.2 Dispense sterilized nutrient agar cooledto45土29C(113土4°F)by pouring 15.0 + 2.0 mL into cach 100.0 mim diametcr flat bottomed Petri dish. Allow agar 1o gel firmly before inoculating. 11.3 Preparc inoculum by transferring 1.0+0.1 mL of a 24 h broth culture into 9.0土0.1 mL of sterile distilled water conained in a lest tube or small flask. Mix well using appropriate agitation. 11.4 Using a 4 mm inoculating loop. load one loopful of the dilutcd inoculum and transfer it to the surface of the sterile agar plate by making one long streak of approximatly 75 mm in length across the center of the plate. Do not break the sur- face of the agar w hile making the streak. 11.5 Gently press the test specimen transverscly across the inoculum streak to ensure inimate contact with the agar sur- face. An casy techniquc is 1o press the specimen to the agar surface with a biological section lifter or with a spatula which has been sterilized in a flame and then aircooled immediatcly before usc. Test both the pile (face fibers) and the backing of the carpet on separale agar platcs. 11.6 Incubate the platesat 37+ 2°C (99 +3°F) for 18-24 h. 12. Evaluation and Report 12.1 Examine the incubated plates for interruption of growth along the strcak of inoculum bencath the specimen and for a clear zone of inhibition bcyond the specimcn edgc.AATCC 174 pdf download.