Mixture of Sodium Hypochlorite and Hydrogen Peroxide on Adhered Aeromonas hydrophila to Solid Substrate in Water: Impact of Concentration and Assessment of the Synergistic Effect

Abstract

The synergistic effects of the combined treatments of NaOCl and H 2 O 2 on the elimination of A. hydrophila adhered to polythene under static and dynamic conditions were evaluated. The concentrations 0.1, 0.2, and 0.3 ‰ NaOCl and 0.5, 1, and 1.5 ‰ H 2 O 2 were used. The contact periods were 180, 360, 540, and 720 minutes. The abundance of cells adhered reached 2.47 and 2.27 units (log (CFU/cm²)), respectively, under static and dynamic conditions after action of the mixture of disinfectants, whereas it reached 2.41 and 3.39 units (log (CFU/cm²)) after action of NaOCl and H 2 O 2 alone, respectively. Increase in the incubation period resulted in a significant decrease in the abundance of cells adhered when the mixture of 0.3 ‰ NaOCl and 1.5 ‰ H 2 O 2 was used ( P < 0.01 ). For each cell growth phase, there was a significant difference amongst the mean densities of cells adhered after action of the mixture of disinfectants ( P < 0.05 ). Although the Freundlich isotherm parameters relatively varied from one experimental condition to another, the K f value registered in the exponential growth phase was relatively higher in static state than in dynamic regime; cells adhered under dynamic condition seem more sensitive to the synergistic action than those adhered under static condition.