Kinetics of Escherichia coli inactivation employing hydrogen peroxide at varying temperatures, pH and concentrations

Abstract

The effectiveness of hydrogen peroxide on the destruction of planktonic cells of Escherichia coli at different temperatures, pH and sanitizer concentrations was studied. Inactivation kinetics of E. coli exhibited a clear dependence on hydrogen peroxide concentration, pH and temperature. A Weibullian mathematical model successfully described the inactivation curves. Quantitative kinetic results obtained allowed to identify various combinations H2O2 concentration-pH-temperature for 5-log cycles reduction of E. coli. Flow cytometry analysis revealed induced H2O2 cytoplasm membrane damage. TEM observations indicated that H2O2 treatment resulted in rupture of outer and cytoplasm membranes and a more uniform granularity.