Optimization of Cold Plasma Actuator Design for Decontamination of <i>L. monocytogenes</i>

Ma, Li; Ma, Li

Tuesday, July 28, 2015

Hall B (Oregon Convention Center)

Li Ma , Oklahoma State University, National Institute for Microbial Forensics & Food and Agricultural Biosecurity, Department of Entomology and Plant Pathology , Stillwater , OK

Kedar Pai , Oklahoma State University, Department of Mechanical and Aerospace Engineering , Stillwater , OK

Chris Timmons , Oklahoma State University, National Institute for Microbial Forensics & Food and Agricultural Biosecurity, Department of Entomology and Plant Pathology , Stillwater , OK

Weiyu Jiang , National Institute for Microbial Forensics & Food and Agricultural Biosecurity, Department of Entomology and Plant Pathology, Oklahoma State University , Stillwater , OK

Guodong Zhang , U.S. Food and Drug Administration , College Park , MD

Jamey Jacob , Department of Mechanical and Aerospace Engineering, Oklahoma State University , Stillwater , OK

Introduction: As a relatively new microbial inactivation technology, non-thermal or cold plasma has been gaining a lot of interest in food safety applications. Various modes of plasma generation have been explored but most of these designs require high power input and an artificial gas flow, therefore complicating their usages.

Purpose: The objective of this study was to optimize cold plasma actuator design for efficient inactivation of foodborne pathogens.

Methods: Surface Dielectric Barrier Discharge (SDBD) cold plasma devices were constructed with electrodes arrangement either asymmetrically or symmetrically. The airflow dynamic of the devices were evaluated by Particle Image Velocimetry (PIV) and their efficacy in microbial inactivation was examined by using a five-strain cocktail of Listeria monocytogenes that were spot-inoculated onto sterile glass coverslips, placed at various distance (1, 3, 5, and 7 cm) from the plasma source, with inoculated untreated samples as controls.

Results: It was observed that the asymmetric arrangement of electrodes resulted in higher velocities and more turbulent flow than that of symmetric arrangement. The PIV data was supported by microbial inactivation data, in which significant (P < 0.05) higher log reduction of inoculated L. monocytogenes was achieved by the devices with asymmetric arrangement of electrodes than those of symmetric ones, with log reductions of 4.8 ± 0.5 vs 3.5 ± 0.5 at 1 cm and 2.3 ± 0.3 vs 1.1± 0.2 at 3 cm for asymmetric and symmetric devices, respectively.

Significance: These data show that the arrangement of electrodes in cold plasma device had significant effect on its efficacy in inactivation of L. monocytogenes and such optimization could be explored in the design of simpler cold plasma device.

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P3-59 Optimization of Cold Plasma Actuator Design for Decontamination of L. monocytogenes