ISO 13629-2: 2014. Textiles-Determination of antifungal activity of textile products- Part 2: plate count method.
Test accredited by ENAC (Spanish National Accreditation Entity).
Part 2 of ISO 13629 Standard specifies a test procedure for the quantitative determination of antifungal activity by the plate count method. This test determinate whether a tissue with an incorporated antifungal treatment exhibits fungistatic or fungicidal activity. It is applicable to various kinds of textile products such as fibers, yarns, fabrics, clothing, bedclothes, home furnishings, and others.
To perform this test, six test specimens from the test fabric and six control specimens from the control fabric (equal to the test samples, but without the antifungal treatment) are inoculated with a spore suspension of reference fungi (Aspergillus niger ≈ Aspergillus brasiliensis). Three replicate specimens of each type of fabric are used to determine the counts of fungi present in the samples at time zero, immediately after inoculation. The remaining three control and test fabric specimens are incubated at 30°C for 48 hours and subsequently they are also counted. To perform the plate count method, the samples are shaken in a neutralizing solution from which dilutions are prepared that are inoculated onto medium in Petri dishes with SDA medium to determine the number of fungi present in specimens. Comparing the logarithms of the counts at time zero and after 48 hours of incubation, the growth value observed on the control and treated textile samples is obtained. To obtain the antifungal activity value (A), the growth value on the control and the antifungal-treated samples are compared. The value of A and the average of counts obtained in the antifungal-treated samples after 48 hours of incubation will determine whether or not the tissue presents fungistatic or fungicidal activity.
If the value of A is less than 1 (A < 1) it is considered that the treated fabric has no antifungal effect; if A is between 1 and 2 (2 > A > 1), it is considered that the fabric is fungistatic with small effect; A values between 2 and 3 (3> A> 2) indicate that the test fabric is fungistatic with medium effect; while if A is greater than 3 (A > 3) the product is considered as fungistatic with full effect. Ultimately, if the average count obtained from the samples of the treated fabric after 48 hours is 0 CFU, it is considered that the test fabric shows fungicidal effect.
To perform this test, two different methods of sample inoculation can be used: the absorption method or the transfer method. In case the test specimen absorbs water, the absorption method is recommended. In case the test specimen do not absorb water, the transfer method is recommended. To perform these two methods, the preparation of the test specimens is different:
- For samples that absorb water (absorption method), specimens with a mass of 0.40 ± 0.05 g and a suitable size for the test are required. If possible, a single 0.4g piece; The size of the specimens depends on the type of fabric.
- For samples that do not absorb water, specimens with a diameter of 3.8 ± 0.1 cm are required (transfer method). Samples must not contain seams, selvages, embroidery, zippers, etc.
The client must send a minimum of 12 antifungal treated specimens and 12 control specimens from the control fabric, prepared as indicated. Control fabric should be the same as the fabric to be tested but without antifungal treatment. If this is not available, the test could be performed using 100% cotton fabric for control specimens (in this case it should be indicated in the request form).
To request the test, the customer must indicate on the submission form: the fungi chosen for testing and the inoculation method to use (depending on whether the fabric absorb or not water).