Effectiveness of Aqueous Chlorine Dioxide in Minimizing Food Safety Risk Associated with Salmonella, E. coli O157:H7, and Listeria monocytogenes on Sweet Potatoes.

Phillip Luu,Marlene E Janes,Joan M King,Achyut Adhikari,Vijay Singh Chhetri

doi:10.3390/foods9091259

Phillip Luu, Marlene E Janes + Show 3 more

Open Access

https://doi.org/10.3390/foods9091259

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Abstract

Sodium hypochlorite (NaOCl) is a commonly used sanitizer in the produce industry despite its limited effectiveness against contaminated human pathogens in fresh produce. Aqueous chlorine dioxide (ClO2) is an alternative sanitizer offering a greater oxidizing potency with greater efficacy in reducing a large number of microorganisms. We investigated the effect of aqueous chlorine dioxide treatment against human pathogens, Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes seeded on sweet potatoes. Sweet potatoes were spot inoculated (4.2 to 5.7 log CFU/cm2) with multi-strain cocktails of Salmonella spp., E. coli O157:H7, and L. monocytogenes and treated for 10–30 min with 5 ppm aqueous ClO2 or water. Aqueous ClO2 treatment was significantly (p < 0.05) effective in reducing Salmonella with a reduction of 2.14 log CFU/cm2 within 20 min compared to 1.44 log CFU/cm2 for water treatment. Similar results were observed for L. monocytogenes with a 1.98 log CFU/cm2 reduction compared to 0.49 log CFU/cm2 reduction observed after 30 min treatment with aqueous ClO2 the water respectively. The maximum reduction in E. coli O157: H7 reached 2.1 Log CFU/cm2 after 20 min of treatment with aqueous ClO2. The level of the pathogens in ClO2 wash solutions, after the treatment, was below the detectable limit. While in the water wash solutions, the pathogens’ populations ranged from 3.47 to 4.63 log CFU/mL. Our study indicates that aqueous ClO2 is highly effective in controlling cross-contamination during postharvest washing of sweet potatoes.

Highlights

Growing global populations have greatly increased the demand of wholesome fresh produce including sweet potatoes
1.98 log CFU/cm2 reduction compared to 0.49 log CFU/cm2 reduction observed after 30 min treatment with aqueous ClO2 the water respectively
Our study indicates that aqueous ClO2 is highly effective in controlling cross-contamination during postharvest washing of sweet potatoes

Summary

Introduction

Growing global populations have greatly increased the demand of wholesome fresh produce including sweet potatoes. The global sweet potato market has been on the rise since 2012, producing. Sweet potatoes are recognized as nutritiously potent crops consumed and researched globally [2,3]. The sweet potato is potentially an ideal and efficient crop for providing sustenance for much of the world as well as being a viable crop for sustainable agriculture [2,4]. The majority of sweet potatoes are produced by developing countries where the usage of raw manure as fertilizer is still common practice. In addition to pathogens found in raw manure, contaminated irrigation water and wildlife excrements pose potential threats to soil contamination

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