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

Abstract

An aseptic tank model system was used to study the efficacy of chlorine dioxide (ClO2) gas as a potential sanitizing agent for commercial epoxy-lined juice storage tanks. Selected spoilage micro-organisms (Lactobacillus buchneri, Leuconostoc mesenteroides, Eurotiumspp.,Penicilliumspp,Candidaspp. andSaccharomyces cerevisiae) were surface inoculated on to epoxy-coated stainless steel strips, placed in the model tank and subjected to different ClO2gas treatments. The varied treatment conditions consisted of 2–14 mg l−1ClO2gas, 50–98% relative humidity, 5–120 min exposure time, and temperatures ranging from 9–31°C.L. buchneriwas used as the target micro-organism and was found to be most resistant to selected ClO2gas treatments, followed byL. mesenteroides, followed by the yeasts and molds studied. Inactivation ofL. buchneriandL. mesenteroidesincreased with greater concentration of ClO2gas, 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−1ClO2gas for an exposure time of 30 min coupled with (a) high relative humidity (>90%) and holding temperatures between 9 and 28°C, or (b) high holding temperatures (25–28°C) and relative humidity above 69%.