Research Papers : Antibacterial Activity of Chitosan Acetate on Bacteria Associated with Food-borne Disease

survival fraction Antibacterial activity of chitosan acetate (MW ca. 60 kDa) was examined against five different bacterial strains involved in food-borne disease; Bacillus anthracis, Bacillus cereus, Serratia marcescens, Escherichia coli O157, and Vibrio vulnificus. Effect of chitosan acetate on five bacterial strains was investigated by measuring the minimum inhibitory concentration (MIC) and survival fractions of these bacteria at 1/2MIC and MIC of chitosan acetate. The minimum inhibitory concentrations (MICs) of chitosan against these bacterial strains were ranging from 0.03% > to > 0.08%. The MICs for B. anthracis, B. cereus, and V. vulnificus were ca. 0.03%, whereas those of E. coli O157 and S. marcescens were 0.05% and 0.08%, respectively. Scanning Electron Microscopy (SEM) of the chitosan treated-bacteria showed that bacterial cells was certainly damaged, resulting in structural irregularity including elongated cells or disintegrated shape.