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High Voltage Atmospheric Cold Air Plasma Control Of Bacterial Biofilms On Fresh Produce, Apurva Patange, D. Boehm, Dana Ziuzina, Patrick Cullen, Brendan Gilmore, Paula Bourke
High Voltage Atmospheric Cold Air Plasma Control Of Bacterial Biofilms On Fresh Produce, Apurva Patange, D. Boehm, Dana Ziuzina, Patrick Cullen, Brendan Gilmore, Paula Bourke
Articles
Atmospheric cold plasma (ACP) offers great potential for decontamination of food borne pathogens. This study examined the antimicrobial efficacy of ACP against a range of pathogens of concern to fresh produce comparing planktonic cultures, monoculture biofilms (Escherichia coli, Salmonella enterica, Listeria monocytogenes, Pseudomonas fluorescens) and mixed culture biofilms (Listeria monocytogenes and Pseudomonas fluorescens). Biotic and abiotic surfaces commonly occurring in the fresh food industry were investigated. Microorganisms showed varying susceptibility to ACP treatment depending on target and process factors. Bacterial biofilm populations treated with high voltage (80 kV) ACP were reduced significantly (p < 0.05) in both mono- and mixed species biofilms after 60 s of treatment and yielded non-detectable levels after extending treatment time to 120 s. However, an extended time was required to reduce the challenge mixed culture biofilm of L. monocytogenes and P. fluorescens inoculated on lettuce, which was dependent on biofilm formation conditions and substrate. Contained treatment for 120 s reduced L. monocytogenes and P. fluorescens inoculated as mixed cultures on lettuce (p < 0.05) by 2.2 and 4.2 Log10 CFU/ml respectively. When biofilms were grown at 4 °C on lettuce, there was an increased resistance to ACP treatment by comparison with biofilm grown at temperature abuse conditions of 15 °C. Similarly, L. monocytogenes and P. fluorescens exposed to cold stress (4 °C) for 1 h demonstrated increased tolerance to ACP treatment compared to non-stressed cells. These finding demonstrates that bacterial form, mono versus mixed challenges as well as environmental stress conditions play an important role in ACP inactivation efficacy.
Atmospheric Cold Plasma Inactivation Of Escherichia Coli, Salmonella Enterica Serovar Typhimurium And Listeria Monocytogenes Inoculated On Fresh Produce, Dana Ziuzina, Sonal Patil, Patrick Cullen, Kevin Keener, Paula Bourke
Atmospheric Cold Plasma Inactivation Of Escherichia Coli, Salmonella Enterica Serovar Typhimurium And Listeria Monocytogenes Inoculated On Fresh Produce, Dana Ziuzina, Sonal Patil, Patrick Cullen, Kevin Keener, Paula Bourke
Articles
Atmospheric cold plasma (ACP) represents a potential alternative to traditional methods for non-thermal decontamination of foods. In this study, the antimicrobial efficacy of a novel dielectric barrier discharge ACP device against Escherichia coli, Salmonella enterica Typhimurium and Listeria monocytogenes inoculated on cherry tomatoes and strawberries, was examined. Bacteria were spot inoculated on the produce surface, air dried and sealed inside a rigid polypropylene container. Samples were indirectly exposed (i.e. placed outside plasma discharge) to a high voltage (70kVRMS) air ACP and subsequently stored at room temperature for 24 h. ACP treatment for 10, 60 and 120 s resulted in reduction …