Effect of gaseous chlorine dioxide treatment on the quality of rice and wheat grain

Gaseous chlorine dioxide (ClO₂), which is a strong disinfecting agent with strong oxidation properties and penetration ability, is used to control insect pests and fungal contamination in stored grains. However, the effect of gaseous ClO₂ on stored grain has yet to be reported. In the present study, we exposed rice and wheat seeds to several concentrations of ClO₂ gas for various durations and found that the viability of rice was affected less than that of wheat. After 100 ppm of gaseous ClO₂ for 12 h, the normal rice seedling rate was not significantly different than that of the control. However, that of wheat was significantly decreased. We also measured the ClO₂ residueon stored rice and wheat after 200 ppm of gas treatment for 24 h. After 10 days of storage following the treatment, ClO₂ and chlorine were not detected on either rice or wheat. Chlorite was detected on rice at 0.22 mg/kg of grain; however, it was not detected on wheat. These results suggest that gaseous ClO₂ treatment affects the viability of rice and wheat seed but leaves minimal chemical residue.