A pilot‐scale evaluation of using gaseous chlorine dioxide for decontamination of foodborne pathogens on produce and low‐moisture foods

Abstract

AbstractSmall‐scale studies have shown that chlorine dioxide gas, ClO2(g), was effective for decontamination of produce, nuts, and spices. This study conducted a pilot‐scale evaluation to identify effective ClO2(g) treatment parameters for commercial‐scale applications. The gas was produced by a generator utilizing sodium chlorite and chlorine gas for decontamination of Shiga toxin‐producing Escherichia coli (STEC), Listeria monocytogenes, and Salmonella inoculated on tomatoes, blueberries, baby‐cut carrots, almonds, and peppercorns. Inoculated samples and 45 kg tomatoes in a 1,246‐L treatment chamber were exposed to various ClO2(g) concentrations (mg/L) and times 9 (hr) at 70–95% RH to determine the treatment effects on the pathogen reductions. Results showed that the treatment caused higher reductions on produce. A ClO2(g) treatment of 1 mg/L‐3 hr at 70% RH reduced 4.9–6.8, 5.1–5.6, and 4.2–6.3 log CFU/g of STEC, L. monocytogenes, and Salmonella, respectively, on produce, with the highest reductions on baby‐cut carrots. For almonds and peppercorns, ClO2(g) treatments under higher RH caused higher reductions. The treatment of 2 mg/L‐9 hr or 3 mg/L‐4 hr at 95% RH reduced >4.0 log of STEC and Salmonella on almonds, and 1 mg/L‐5 hr at 85% RH achieved >5.0 log reductions on peppercorns. Applying moisture to the surfaces of almonds caused >4.0 log reductions using 1 mg/L‐5 hr at 95% RH. This study identified effective ClO2(g) treatment parameters for achieving >4.0 log reductions of common pathogens on tomatoes, blueberries, baby‐cut carrots, almonds, and peppercorns and showed that ClO2(g) generator is suitable for large‐scale decontamination. These findings can be used for pilot‐scale ClO2(g) decontamination of these products and for testing using ClO2(g) for commercial‐scale decontamination trials.