Efficacy of chlorine dioxide gas as a sanitizer for tanks used for aseptic juice storage

摘要

An aseptic tank model system was used to study the efficacy of chlorine dioxide (ClO_2) gas as a potential sanitizing agent for commercial epoxy-lined juice storage tanks. Selected spoilage micro-organisms (Lactobacillus buchneri, Leuconostoc mesenteroides, Eurotium spp., Penicillium spp, Candida spp. and Saccharomyces cerevisiae) were surface inoculated on to epoxy-coated stainless steel strips, placed in the model tank and subjected to different ClO_2 gas treatments. The varied treatment conditions consisted of 2-14 mg l~(-1) ClO_2 gas, 50-98 relative humidity, 5-120 min exposure time, and temperatures ranging from 9-31 deg C. L. buchneri was used as the target micro-organism and was found to be most resistant to selected ClO_2 gas treatments, followed by L. mesenteroides, followed by the yeasts and molds studied. Inactivation of L. buchneri and L. mesenteroides increased with greater concentration of ClO_2 gas, higher holding temperature, higher relative humidity, and more exposure time. Under the conditions of this study, all the selected micro-organisms could be completely inactivated, resulting in a sterilized surface. The recommended treatments for assuring sterility were 10 mg l~(-1) ClO_2 gas for an exposure time of 30 min coupled with (a) high relative humidity (> 90) and holding temperatures between 9 and 28 deg C, or (b) high holding temperatures (25-28 deg C) and relative humidity above 69.