GB/T 20944.2-2007Textiles - Evaluation for antibacterial activity - Part 2: Absorption method (English PDF)

3.1 Antibacterial activity

The performance of product to inhibit the reproduction of bacteria.

3.2 Control fabric

A 100% cotton fabric, which does not subject to any treatment, is used to verify the growth conditions of the test bacteria.

6.1 Spectrophotometer. Detection wavelength 660 nm

6.4 Constant temperature speed-regulating shaker cabinet

6.9 Vortex oscillator

6.10 Two-stage biological safety cabinet

7.1 Soy protein broth (TSB)

7.4 SCDLP liquid medium

7.5 Diluent

8.1 Strains

The following Gram-positive and one of the Gram-negative strains shall be used.

8.2 Activation of freeze-dried bacteria

The freeze-dried bacteria are thawed and dispersed in 5 mL of TSB (7.1) into a suspension state. It is cultured at 37 °C ± 2 °C for 18 h ~ 24 h.

8.3 Identification

The following information shall be marked for each test bacteria.

9.3 Culture C

Take 20 mL of broth NB (7.3) or TSB (7.1), into a 100 mL conical flask. Take 0.4 mL of bacterial solution from culture B (9.2) AND add it to the flask for culture. The concentration of the cultured bacteria is 107 CFU/mL.

9.4 Preparation of test bacterial solution

Use water to dilute the broth NB (7.3) 20 times. Adjust the bacterial concentration of culture C (9.3) to 1 x 10^5 CFU/mL ~ 3 x 10^5 CFU/mL, which is used as the test bacterial solution.

10.1 Sample washing

If evaluating the antibacterial and washing resistance performance, take 3 small samples from each large sample (each size is 10 cm x 10 cm; cut into 2 pieces).

Wash it, according to the test condition A1M in GB/T 12490-1990. Use the ECE standard detergent.

10.2 Specimen mass

Select a representative specimen from each sample. Cut it to an appropriate size. Weigh 0.40 g ± 0.05 g as a specimen. Take 3 specimens for the test of antibacterial activity, AND 6 control fabrics, respectively.

10.3 Placement of specimen

Place each specimen in a small glass bottle.

10.4 Sterilization of specimen

Choose the sterilization method according to the fiber and treatment type of the specimen. Generally, autoclave sterilization is used.

11.1 Inoculation of specimen

Respectively pipette accurately 0.2 mL of the test bacterial solution (9.4); inoculate it to the specimen (10.3 or 10.4) in each vial. Ensure that the bacterial solution does not stick to the wall of the vial. Apply the cap tightly.

Note: In order to immerse the bacterial solution on the specimen, a test bacterial solution, which contains 0.05% non-ionic surfactant, can also be used. However, it shall be indicated in the test report.

11.2 Elution immediately after inoculation

Add 20 mL of SCDLP medium (7.4), into the 3 control fabric vials (11.1), which had been inoculated with the test bacteria solution. Close the cap tightly. Use hands to shake it for 30 s (swing about 30 cm). OR otherwise use a shaker to shake 5 times (5 s each time), to wash off the bacteria.

11.3 Cultivation

Culture the remaining 6 vials (3 control fabrics and 3 specimens), which had been inoculated with the test bacteria solution, at 37 °C ± 2 °C for 18 h ~ 24 h.

11.4 Elution after cultivation

After culture (11.3), add 20 mL of SCDLP medium (7.4) to each vial. Close the cap tightly. Use hands to shake it for 30 s (swing about 30 cm). OR otherwise use a shaker to shake it 5 times (5 s each time), to wash off the bacteria. […]