BACTERICIDAL ACTIVITY OF AQUEOUS CHLORINE AND CHLORINE DIOXIDE SOLUTIONS IN A FISH MODEL SYSTEM

A commercial ClO2-producing solution killed mostly Escherichia coli, L isteria monocytogenes Scott A and its streptomycin-resistant (Str(R)) strain at 15, 10, and 7.5 ppm, respectively, while aqueous ClO2 and ch lorine achieved similar results against the tested strains at 20 and 2 5 ppm. respectively, Aqueous ClO2 and the commercial solution were mor e effective than aqueous chlorine in killing Str(R)-L. monocytogenes i noculated on fish cubes (mangrove snapper) at 3.4 x 10(3) or 2.4 x 10( 6) CFU/g, as well as in solutions washed off the cubes. Fish cubes tre ated with aqueous chlorine or ClO2 contained negligible chlorine resid ues while the commercial treatment samples contained chlorite and some free and combined available chlorine.