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P3-56 Cold Plasma Inactivation of Salmonella enterica, Shiga Toxin-producing Escherichia coli, and Listeria monocytogenes by a Novel Surface Dielectric Barrier Discharge Device

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
Chris Timmons , 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
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: Atmospheric cold plasma offers a dry, non-thermal, and rapid process for decontamination of food products and a novel cold plasma device based on Surface Dielectric Barrier Discharge (SDBD) has been developed in our laboratory.

Purpose: The objective of this study was to evaluate the inactivation efficacy of the SDBD-based cold plasma device against the major foodborne pathogens Salmonella enterica (Se), Shiga Toxin-producing Escherichia coli (STEC), and Listeria monocytogenes (Lm).

Methods: Five-strain cocktails of Se, STEC, or Lm cultures (107 CFU/sample) were spot inoculated onto sterile glass cover slips, air dried, and treated at various distances (1, 3, 5, and 7 cm) from the cold plasma actuators for different treatment times (2 and 4 min). Log reductions, calculated by comparing with inoculated untreated samples as controls, obtained from at least two replicating trials, were used to determine decimal reduction times (D-values) at each distance for each pathogen mixture.

Results: Inactivation of bacterial cells was observed at all distances and at both treatment times but with decreasing efficiency at increasing distance. Average log reductions for 4 min treatments at 1 cm were 4.1 for Se, 3.4 for STEC, and 2.3 for Lm. D-values (min) at 1 cm for Se, STEC, and Lm were 1.3, 0.9, and 1.8, respectively. These results confirm that the SDBD design induces a localized airflow that contains reactive species that decreases with distance from the actuator and that treatment time has an additive effect rather than a compounding effect.

Significance: This study confirms the ability to inactivate bacterial pathogens with cold plasma by SDBD and that induced airflow is the means of reactive species delivery to contaminated surfaces.

Back to: Poster Session 3 – Laboratory and Detection Methods, Sanitation; Antimicrobials; Produce; Epidemiology
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