When oxygen saturation was performed by anodic treat-ment, the number of E. coli cells (CFU) following the overnight incubation with such chitosan was about 100-fold lower comparingto that with untreated chitosan. In the case of direct oxygen satura-tion, the antibacterial properties of chitosan were much distinctly expressed. The amount of viable E. coli cells was about 3000-foldlower than that in control samples