AATCC TM100-2019 Test Method for Antibacterial Finishes on Textile Materials: Assessment of.
7. Preparation of Bacterial Inocula
7.1 Grow a fresh 18-h shake culture of each test specimen in sterile Tryptic Soy (or Nutrient) broth at 37 ± 2°C and 150- 250 rpm prior to performing the test. These cultures should originate from a single colony selected from stock culture plates or growth on agar slants. Fresh stock plates should be generated weekly.
7.1.1 Each 18-h shake culture is then diluted with suspension medium (6.1.6), as appropriate for the estimated bacterial concentration, to obtain a bacterial concentration that is between 1.0 × 10 5 and 3.0 × 10 5 CFU/mL. These suspensions are used as the test inoculum. Prepared test inoculum is used within 2 h of prepa- ration and bacterial concentration should be verified by appropriate enumeration method.
8. Test Specimens
8.1 Preparation. The following descrip- tion will be in terms of fabric swatches. Textile materials not in fabric form can likewise be tested with the appropriate modification.
8.1.1 Size and shape of test swatches: Cut circular swatches 4.8 ± 0.1 cm (1.9 ± 0.03 in.) in diameter or square swatches 3.8 × 3.8 ± 0.1 cm, from the test fabric. Use the number of swatches needed to equal 1.0 ± 0.1g. Stack the swatches in a sterile specimen container with screw cap or other appropriate closed container. The number of swatches to be used is depen- dent on the fiber type and fabric construc- tion. The number of swatches used per jar should be reported. 8.1.2 Untreated Controls. Swatches of the same fiber type and fabric construction as test sample but containing no anti- bacterial finish will be required if calculating percent reduction using formula outlined in 10.2.
8.1.3 Viability Controls. Viability con- trol fabric is required and should be known to demonstrate > 1 log bacterial growth as defined in 10.4.
8.1.4 Test specimens should not be sterilized prior to testing. If sterilization is performed, method and reason for ster- ilization must be noted on the test report.
9.1 Size of inoculum per sample. Ap- ply 1.0 ± 0.1 mL of test inoculum (7.1.1) so that recovery from (1) viability control fabric swatches or (2) test fabric swatches at “0” contact time (plated as soon as possible after inoculation) will show counts of 1-3 × 10 5 organisms.
9.1.1 As soon as possible after inoculation (“0” contact time), add 100 ± 1 mL of neutralizing solution to each of the jars containing the inoculated untreated control swatches, the inoculated test swatches and the viability control fabric swatches.
9.1.2 The neutralizing solution should include ingredients to neutralize the specific antibacterial fabric treatment and to take care of any pH requirements of the fabrics (from finishes, antibacterial agents, etc.). The neutralizing solution employed should be reported.AATCC TM100 pdf download.