Feasibility and efficacy of using gaseous chlorine dioxide generated by sodium chlorite-acid reaction for decontamination of foodborne pathogens on produce

Abstract

The objective of this study was to evaluate the feasibility and efficacy of using chlorine dioxide (ClO2) gas generated by dry media (sodium chlorite and ferric chloride) and sodium chlorite-hydrogen chloride dosing methods for decontamination of foodborne pathogens on produce. Tomatoes, blueberries, and baby-cut carrots inoculated with Shiga toxin-producing Escherichia coli, Salmonella, and Listeria monocytogenes were treated with ClO2 gas in a pilot-scale decontamination process. The effects of cumulative ClO2 exposure, i.e., ClO2 concentration (ppm) × treatment time (h) (ppm-h), on the reductions of inoculated pathogens were determined. Results showed that the increase of cumulative ClO2 exposure between 300 and 1900 ppm-h increased the log reductions of pathogens on produce, whereas no significant increase in log reductions was observed after 1900 ppm-h. The cumulative ClO2 exposures of 300, 1300, and 1600 ppm-h caused >4.0-log CFU/g reductions of the pathogens on baby-cut carrots, tomatoes, and blueberries, respectively. The treatment was most effective against the pathogens on baby-cut carrots, likely due to the moisture on the surface of the peeled carrots. This study showed that the two ClO2 generation methods are suitable and effective for decontamination of produce. The correlation between the cumulative ppm-h and pathogen reduction was independent of the quantity of products and other factors that may affect the consumption rate of ClO2. Therefore, the treatment parameters obtained from this study can be used for decontamination applications of similar scale or as references for evaluating using ClO2 gas for decontamination of tomatoes, blueberries, and baby-cut carrots in commercial-scale trials.