High voltage atmospheric cold air plasma control of bacterial biofilms on fresh produce

Apurva Patange, Daniela Boehm, Dana Ziuzina, P. J. Cullen, Brendan Gilmore, Paula Bourke*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

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 Log 10 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.

Original languageEnglish
Pages (from-to)137-145
Number of pages9
JournalInternational Journal of Food Microbiology
Volume293
Early online date12 Jan 2019
DOIs
Publication statusPublished - 16 Mar 2019

Keywords

  • Acid and cold stress
  • Atmospheric cold plasma
  • Foodborne pathogens
  • Lettuce
  • Mono/mixed culture biofilms
  • Spoilage bacteria

ASJC Scopus subject areas

  • Food Science
  • Microbiology

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