An Effective Sanitizer for Fresh Produce Production: In Situ Plasma-Activated Water Treatment Inactivates Pathogenic Bacteria and Maintains the Quality of Cucurbit Fruit.

Autor: Rothwell JG; ARC Training Centre for Food Safety in the Fresh Produce Industry, School of Life and Environmental Sciences, Faculty of Science, Sydney Institute of Agriculture, The University of Sydney, Sydney, New South Wales, Australia., Hong J; School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales, Australia., Morrison SJ; Department of Agricultural and Resource Economics, University of California, Davis, California, USA., Vyas HKN; School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales, Australia.; Sydney Institute of Infectious Diseases, The University of Sydney, Sydney, New South Wales, Australia., Xia B; School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales, Australia., Mai-Prochnow A; School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales, Australia., McConchie R; ARC Training Centre for Food Safety in the Fresh Produce Industry, School of Life and Environmental Sciences, Faculty of Science, Sydney Institute of Agriculture, The University of Sydney, Sydney, New South Wales, Australia., Phan-Thien KY; ARC Training Centre for Food Safety in the Fresh Produce Industry, School of Life and Environmental Sciences, Faculty of Science, Sydney Institute of Agriculture, The University of Sydney, Sydney, New South Wales, Australia., Cullen PJ; School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales, Australia., Carter DA; ARC Training Centre for Food Safety in the Fresh Produce Industry, School of Life and Environmental Sciences, Faculty of Science, Sydney Institute of Agriculture, The University of Sydney, Sydney, New South Wales, Australia.; Sydney Institute of Infectious Diseases, The University of Sydney, Sydney, New South Wales, Australia.
Jazyk: angličtina
Zdroj: Microbiology spectrum [Microbiol Spectr] 2023 Aug 17; Vol. 11 (4), pp. e0003423. Date of Electronic Publication: 2023 Jul 10.
DOI: 10.1128/spectrum.00034-23
Abstrakt: The effect of plasma-activated water (PAW) generated with a dielectric barrier discharge diffusor (DBDD) system on microbial load and organoleptic quality of cucamelons was investigated and compared to the established sanitizer, sodium hypochlorite (NaOCl). Pathogenic serotypes of Escherichia coli, Salmonella enterica, and Listeria monocytogenes were inoculated onto the surface of cucamelons (6.5 log CFU g -1 ) and into the wash water (6 log CFU mL -1 ). PAW treatment involved 2 min in situ with water activated at 1,500 Hz and 120 V and air as the feed gas; NaOCl treatment was a wash with 100 ppm total chlorine; control treatment was a wash with tap water. PAW treatment produced a 3-log CFU g -1 reduction of pathogens on the cucamelon surface without negatively impacting quality or shelf life. NaOCl treatment reduced the pathogenic bacteria on the cucamelon surface by 3 to 4 log CFU g -1 ; however, this treatment also reduced fruit shelf life and quality. Both systems reduced 6-log CFU mL -1 pathogens in the wash water to below detectable limits. The critical role of superoxide anion radical (·O 2 - ) in the antimicrobial power of DBDD-PAW was demonstrated through a Tiron scavenger assay, and chemistry modeling confirmed that ·O 2 - generation readily occurs in DBDD-PAW generated with the employed settings. Modeling of the physical forces produced during plasma treatment showed that bacteria likely experience strong local electric fields and polarization. We hypothesize that these physical effects synergize with reactive chemical species to produce the acute antimicrobial activity seen with the in situ PAW system. IMPORTANCE Plasma-activated water (PAW) is an emerging sanitizer in the fresh food industry, where food safety must be achieved without a thermal kill step. Here, we demonstrate PAW generated in situ to be a competitive sanitizer technology, providing a significant reduction of pathogenic and spoilage microorganisms while maintaining the quality and shelf life of the produce item. Our experimental results are supported by modeling of the plasma chemistry and applied physical forces, which show that the system can generate highly reactive ·O 2 - and strong electric fields that combine to produce potent antimicrobial power. In situ PAW has promise in industrial applications as it requires only low power (12 W), tap water, and air. Moreover, it does not produce toxic by-products or hazardous effluent waste, making it a sustainable solution for fresh food safety.
Competing Interests: The authors declare a conflict of interest. P. J. Cullen is the Chief Technology Officer of Plasmaleap Technologies, the supplier of the plasma technology employed to generate plasma bubbles in this study.
Databáze: MEDLINE
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