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

An aseptic tank model system was used to study the efficacy of chlorine dio xide (ClO2) gas as a potential sanitizing agent for commercial epoxy-lined juice storage tanks. Selected spoilage micro-organisms (Lactobacillus buchn eri, 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 rank and subjected to different ClO2 gas treatments. The varied treatment conditions consisted of 2-14 mg l(-1) CIO2 gas, 50-98% relative humidity, 5-120 min exposure time, and temp eratures ranging from 9-31 degrees C. L, buchneri was used as the target mi cro-organism and was found to be most resistant to selected ClO2 gas treatm ents, followed by L. mesenteroides, followed by the yeasts and molds studie d. inactivation of L. buchneri and L. mesenteroides increased with greater concentration of ClO2 gas, higher holding temperature, higher relative humi dity, and more exposure time. Under the conditions of this study, all the s elected micro-organisms could be completely inactivated, resulting in a ste rilized surface. The recommended treatments for assuring sterility were 10 mg l(-1) ClO2 gas for an exposure time of 30 min coupled with (a) high rela tive humidity (> 90%) and holding temperatures between 9 and 28 degrees C, or (b) high holding temperatures (25-28 degrees C) and relative humidity ab ove 69%. (C) 1999 Academic Press.