Bactericidal Activity of Aqueous Chlorine and Chlorine Dioxide Solutions in a Fish Model System

ABSTRACT A commercial ClO 2 ‐producing solution killed mostly Escherichia coli, Listeria monocytogenes Scott A and its streptomycin‐resistant (Str R ) strain at 15, 10, and 7.5 ppm, respectively, while aqueous ClO 2 and chlorine achieved similar results against the tested strains at 20 and 25 ppm, respectively. Aqueous ClO 2 and the commercial solution were more effective than aqueous chlorine in killing Str R ‐ L. monocytogenes inoculated on fish cubes (mangrove snapper) at 3.4 × 10 3 or 2.4 × 10 6 CFU/g, as well as in solutions washed off the cubes. Fish cubes treated with aqueous chlorine or ClO 2 contained negligible chlorine residues, while the commercial treatment samples contained chlorite and some free and combined available chlorine.