In-situ generation of chlorine dioxide for decontamination of whole cantaloupes and sprout seeds

Authors: TAN, JING NI - National Taiwan Ocean University; Hwang, Cheng An; Huang, Lihan; Wu, Vivian; HSIAP, HSIN I - National Taiwan Ocean University

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2019
Publication Date: 1/21/2020
Citation: Tan, J., Hwang, C., Huang, L., Wu, V.C., Hsiap, H. 2020. In-situ generation of chlorine dioxide for decontamination of whole cantaloupes and sprout seeds. Journal of Food Protection. 83:287-284. https://doi.org/10.4315/0362-028X.JFP-19-434.
DOI: https://doi.org/10.4315/0362-028X.JFP-19-434

Interpretive Summary: Surfaces of whole cantaloupes and sprout seeds are susceptible to pathogen contamination, which have caused outbreaks of foodborne illnesses linked to fresh-cut cantaloupe and raw sprouts. This study developed a new method utilizing sodium chlorite (NaClO2) and hydrochloric acid (HCl) for decontamination of pathogens on whole cantaloupes and sprout seeds. Effective treatment parameters were identified for chemical concentration (1.6% NaClO2 and 6 mM HCl), mode of applying the chemicals (sequential spraying for cantaloupes and dipping for sprout seeds), and treatment time (15-min contact time for each chemical). The treatment can be applied to decontaminate whole cantaloupes and sprout seeds to reduce the risk of pathogen contamination on fresh-cut cantaloupe and sprouts.

Technical Abstract: In-situ generation of chlorine dioxide to reduce microbial populations on produce surfaces has been shown to be effective on produce models. This study examined the treatment for decontamination of bacterial pathogens on whole cantaloupes and sprout seeds. Whole cantaloupes, mung beans, and alfalfa seeds were inoculated with Salmonella, Listeria monocytogenes, and Shiga-toxin producing Escherichia coli, treated with NaClO2 solution, dried, and treated with 6 mM HCl (sequential treatment). Controls were samples treated with NaClO2 or HCl (individual treatment). The pathogen populations on samples before and after treatments were enumerated to determine the reductions of pathogen populations by the treatments. The methods of applying NaClO2 and HCl (dipping or spraying), NaClO2 concentrations of 0.4-1.6% for cantaloupes, and treatment times of 5, 15, and 30 min for sprout seeds were evaluated to identify optimal treatment parameters. For cantaloupes treated with spraying with 1.6% NaClO2, the sequential treatment caused significantly higher reductions (6.2-7.7 log CFU/g) than the combined reductions (3.2-5.2 log CFU/g) by the individual treatments. For cantaloupes treated with dipping with 1.6% NaClO2 and with spraying with 0.4 and 0.8% NaClO2, the sequential treatment didn’t cause higher reductions than the individual treatments. For mung beans, sequential 15- and 30-min treatments caused significantly higher reductions of 4.3-5.0 and 4.7-6.7 log CFU/g, respectively. The sequential 15-min treatment also caused high reductions of 5.1-7.3 log CFU/g on alfalfa seeds. This study identified 1.6% NaClO2 and 6 mM HCl for sequential spraying treatment for cantaloupes and for sequential dipping treatment for mung beans and alfalfa seeds that were effective for reducing pathogen populations (>4.0 log reduction) and may be used for decontamination of whole cantaloupes and sprout seeds.