Inactivation of Mycobacterium avium with chlorine dioxide

Abstract

The effects of pH (6–10), temperature (5–30 °C), and disinfectant concentration (0.5–5 mg ClO 2/L) on the kinetics of Mycobacterium avium inactivation with chlorine dioxide were investigated by performing batch experiments in synthetic 0.01 M phosphate and borate buffer solutions. The resulting inactivation curves were generally characterized by a lag phase followed by two subsequent stages, fast and then slow, of pseudo-first-order kinetics consistent with two-population (susceptible and tolerant) kinetics. However, variability that was uncorrelated to experimental conditions was observed; some inactivation curves did not have a lag phase and/or the susceptible population was absent. The inactivation kinetics of the tolerant population was found to be independent of pH and to have temperature dependence according to Arrhenius law with an activation energy of 74.1 kJ/mole. Conservative CT requirements for the inactivation of M. avium with chlorine dioxide were estimated using the most pronounced lag phase observed and absence of the susceptible population.