An Improved Halo Method for Evaluating the Antibacterial Activity of Leather

In order to evaluate leather antibacterial activity rapidly and accurately, an improved halo method was developed based on conventional halo method and the agar diffusion plate method. During the new method, there were two layers of medium, the bottom was sterile medium and the top was medium containing microbes; more than one leather sample could be tested in a culture dish. The antibacterial activities of leather treated by nano-silver, nano-ZnO and butyl paraben against Escherichia coli, Staphylococcus aureus, Aspergillus niger and Rhodotorula mucilaginosa were tested by the new method. The results indicated intraclass correlation coefficient values were greater than 0.7 but the P values were less than 0.05 during improved halo method testing, thus, the repeatability and reliability was comparable or even better than conventional method. Nano-silver showed excellent and broad antibacterial activity and the difference between each antibacterial agent could be observed clearly and intuitively during improved halo method testing. In sum, improved halo method was a fast, accurate, qualitative and quantitative testing method and would be a new choice for evaluating leather antibacterial activity.