Kinetics of the Inactivation of Vibrio parahaemolyticus in Weakly Acidic Sodium Chlorite Solution

Efficacy of sodium chlorite in inactivating Vibrio parahaemolyticus attached to polyethylene terephthalate surfaces

The inactivation of Vibrio parahaemolyticus cells attached to a polyethylene terephthalate (PET) disc in a sodium chlorite (NaClO2) solution was kinetically studied in a weakly acidic pH range of 4.0 - 6.5. The logarithmic reduction in the survival ratio depended on the concentration-time product. All inactivation curves showed a linear reduction phase, and the reduction in viable cells was greater than 4-log. No significant desorption of attached cells was observed during the inactivation treatment. The first-order inactivation rate constant (k) increased by approximately 4.5-fold for every 1.0 unit fall in pH. At all pH values, the k values calculated for the attached cells were approximately half of those for the unattached cells. These findings indicate that a weakly acidic NaClO2 solution is effective in inactivating bacteria attached to hard surfaces.