Efficacy of chlorine dioxide as a gas and in solution in the inactivation of two trichothecene mycotoxins

The efficacy of chlorine dioxide (ClO2) in detoxifying two potential bioterrorism agents, the trichothecene mycotoxins verrucarin A and roridin A, was evaluated. In the first experiment, verrucarin A (1, 5, or 10 mu g) and roridin A (5 or 10 mu g) were each inoculated onto square-inch sections of glass, paper, and cloth and exposed to 1000 ppm Of ClO2 for either 24 or 72 h at room temperature. In the second experiment, verrucarin A and roridin A (1 or 2 ppm in water) were treated with 200, 500, or 1000 ppm ClO2 for up to 116 h at room temperature in light and dark conditions (N=9 per treatment for test and control). A yeast assay using Kluyveromyces marxianus was used to quantify the toxicity of verrucarin A and roridin A. Additionally, high-performance liquid chromatography was performed on selected samples. Results for the first experiment showed that ClO2 treatment had no detectable effect on either toxin. For the second experiment, both toxins were completely inactivated at all tested concentrations in as little as 2 h after treatment with 1000 ppm ClO2. For verrucarin A, an effect was seen at the 500 ppm level, but this effect was not as strong as that observed at the 1000 ppm level. Roridin A toxicity was decreased after treatment with 200 and 500 ppm ClO2, but this was not significant until the 24-h exposure time was reached. These data show that ClO2 (in solution) can be effective for detoxification of roridin A or verrucarin A at selected concentrations and exposure times.