Production And Stability Of Chlorine Dioxide In Organic Acid Solutions As Affected By Ph, Type Of Acid, And Concentration Of Sodium Chlorite, And Its Effectiveness In Inactivating Bacillus Cereus Spores

摘要

We studied the production and stability of chlorine dioxide (ClO_2) in organic acid solutions and its effectiveness in killing Bacillus cereus spores. Sodium chlorite (5000,10,000, or 50,000 ng/ml) was added to 5% acetic, citric, or lactic acid solution, adjusted to pH 3.0,4.0, 5.0, or 6.0, and held at 21 ℃ for up to 14 days. The amount of ClO_2 produced was higher as the concentration of sodium chlorite was increased and as the pH of the acid solutions was decreased. However, the stability in production of ClO_2 was enhanced by increasing the pH of the organic acid solutions. To evaluate the lethal activity of ClO_2 produced in various acid solutions as affected by acidulant and pH, suspensions of B. cereus spores were treated at 21 ℃ for 1, 3, 5, or 10 min in hydrochloric acid or organic acid solutions (pH 3.0,4.0, 5.0, or 6.0) containing ClO_2 at concentrations of 100, 50, or 25 Mg/ml. Populations of viable spores treated with ClO_2 at concentrations of 100 or 50μg/ml in organic acid solutions decreased more rapidly than populations treated with the same concentrations of ClO_2 in HC1. Rates of inactivation tended to increase with higher pH of ClO_2 solutions. Results show that ClO_2 formed in organic acid solutions has higher stability and is more lethal to B. cereus spores than ClO_2 formed at the same concentration in HCl solution. This finding emphasizes the benefits of using organic acid solutions to prepare ClO_2 intended for use as an antimicrobial.