Development of sustained release formulations of chlorine dioxide gas for inactivation of foodborne pathogens on produce.

Formulations for the sustained release of chlorine dioxide (ClO) gas were developed, and their gas-producing profiles and antimicrobial effects against O157:H7 and Typhimurium were evaluated in spinach leaves and tomatoes under different relative humidity (RH) conditions. Sodium chlorite (NaClO) and citric acid were used to generate ClO gas, and the generation rate and maximum ClO gas concentration were controlled using diatomaceous earth (DE) and calcium chloride (CaCl). Under 90% RH conditions, sustained release of ClO gas was achieved in presence of DE. When 12 g of DE was added to the mixture, the ClO gas concentration remained constant at 18 ± 1 ppmv for approximately 28 h. At 50% RH, addition of CaCl was effective in maintaining a constant ClO gas concentration. When 0.05 g of CaCl was added to mixtures containing 0.5 g of DE, ClO gas concentration remained constant at 11 ± 1 ppmv for approximately 26 h. Treatment with 30 ppmv of ClO gas at 90% RH achieved more than 6.16 and 5.48 log reductions of O157:H7 and . Typhimurium on spinach leaves (in 15 min), and more than 6.78 and 6.34 log reductions of the same in tomatoes (in 10 min). The sustained release formulations for ClO gas, developed in this study, could facilitate the use of ClO gas as an antimicrobial agent in the food industry.