AATCC Test Method 174 Part I – Qualitative Assessment of – Antibacterial Activity on Carpets: Single Streak Method

This qualitative test method is designed to demonstrate the antibacterial efficacy of a new carpet material. Test Specimens are placed in intimate contact with the agar surface, which has been previously streaked with a bacterial culture. After incubation, a clear area of interrupted growth underneath and along the sides of the test material indicates antibacterial activity of the specimen.

Why This Testing is Performed

The test is performed to test the efficacy of the new Carpet material (fiber and back side) used in healthcare setting, other places, or in a regulated environment.
Test Organisms: Staphylococcus aureus ATCC 6538, Klebsiella pneumoniae ATCC 4352
Test Specimen: Non-sterile, treated and untreated samples (same as test material minus the antibacterial agent).

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Steps in Conducting This Test

1. Test Sample Preparation: Rectangular swatches of the test and control samples are cut to specified dimensions.
2. Test Organism Preparation: The test organisms are prepared by thoroughly mixing an appropriate volume (1:10) of a 24-hour culture and sterile water. Using a sterile inoculating loop, one loopful of the diluted culture is transferred onto a pre-poured Petri plate containing the appropriate media as a single line in the center of the plate.
3. Test Sample Placement: Precut rectangular swatches of the test specimen are gently placed/pressed transversely across the culture line to provide good contact with the agar surface. Both the fiber and the back side of the carpet are tested on separate agar plates.
4. Incubation: Inoculated plates containing the test specimen are then incubated at 37°C for 21±3 hours.
5. Antibacterial Activity Assessment: After incubation, the plates are removed from the incubator and examined for an interruption of growth along the streaked culture line beneath the sample and around the sample for a clear zone of inhibition. Inhibition underneath the test specimen and the zone of inhibition around the sample demonstrate antibacterial properties.

Standards, Guidance, and Regulations

• AATCC Test Method 174 Part I: The primary standard for assessing antimicrobial activity in textiles.