Testing for antibacterial properties of cotton/flax denim

Abstract

The ‘AATCC Test Method 100-1999, Antibacterial Finishes on Textile Materials: Assessment of’ was modified by not assaying for the initial population density and only reporting the population density at the end of incubation for comparing treatments. This seemed to be a reasonable change since the assay challenges the treatments at the start with the same population inoculum density. This permitted the AATCC Test Method 100-1999 to be flexible and easier for testing materials that may or may not actually exhibit bacteriostatic properties. A substantial savings in material and time was gained by not taking the initial population density. This change allows testing more treatments, using more replicate samples, or shortens the time to conduct the assay which can permit more assays to be conducted. However, the control treatment needs to be integral with each assay; but since this is usually done, this would be a small inconvenience compared to the savings. The assay responded well when used to test fabric containing variable amounts of material with known antibacterial properties. The population density of the challenge bacteria decreased as the concentration of the antibacterial component of the fabric increased. The results from the use of the modified AATCC Test Method 100-1999 assay did not indicate that adding flax provided any additional bacteriostatic properties to the flax denim against the two challenge bacteria, Staphylococcus aureus and Klebsiella pneumoniae. The long held assumption that flax is bacteriostatic or antibacterial was not supported by the results and probably does not contribute to its resistance to rotting as much as its physical or chemical composition.