title: Dielectric barrier discharge atmospheric cold plasma inhibits Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Tulane virus in Romaine lettuce.
abstract: The present study investigated the effects of dielectric barrier discharge atmospheric cold plasma (DACP) treatment on the inactivation of Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Tulane virus (TV) on Romaine lettuce, assessing the influences of moisture vaporization, modified atmospheric packaging (MAP), and post-treatment storage on the inactivation of these pathogens. Romaine lettuce was inoculated with E. coli O157:H7, Salmonella, L. monocytogenes (~6logCFU/g lettuce), or TV (~2logPFU/g lettuce) and packaged in either a Petri dish (diameter: 150mm, height: 15mm) or a Nylon/polyethylene pouch (152×254mm) with and without moisture vaporization. Additionally, a subset of pouch-packaged leaves was flushed with O2at 5% or 10% (balance N2). All of the packaged lettuce samples were treated with DACP at 34.8kV for 5min and then analyzed either immediately or following post-treatment storage for 24h at 4°C to assess the inhibition of microorganisms. DACP treatment inhibited E. coli O157:H7, Salmonella, L. monocytogenes, and TV by 1.1±0.4, 0.4±0.3, 1.0±0.5logCFU/g, and 1.3±0.1logPFU/g, respectively, without environmental modifications of moisture or gas in the packages. The inhibition of the bacteria was not significantly affected by packaging type or moisture vaporization (p>0.05) but a reduced-oxygen MAP gas composition attenuated the inhibition rates of E. coli O157:H7 and TV. L. monocytogenes continued to decline by an additional 0.6logCFU/g in post-treatment cold storage for 24h. Additionally, both rigid and flexible conventional plastic packages appear to be suitable for the in-package decontamination of lettuce with DACP.
authors: United States Department of Agriculture, Eastern Regional Research Center, 600 Mermaid Lane, Wyndmoor, PA 19038, USA; Department of Food Science and Technology, Seoul Women's University, 621 Hwarangro, Nowon-gu, Seoul 139-774, Republic of Korea.
authors: Sea C
authors: SC
authors: Min
authors: United States Department of Agriculture, Eastern Regional Research Center, 600 Mermaid Lane, Wyndmoor, PA 19038, USA; Department of Food Science and Technology, Seoul Women's University, 621 Hwarangro, Nowon-gu, Seoul 139-774, Republic of Korea.
authors: Si Hyeon
authors: SH
authors: Roh
authors: United States Department of Agriculture, Eastern Regional Research Center, 600 Mermaid Lane, Wyndmoor, PA 19038, USA. Electronic address: Brendan.Niemira@ars.usda.gov.
authors: Brendan A
authors: BA
authors: Niemira
authors: United States Department of Agriculture, Eastern Regional Research Center, 600 Mermaid Lane, Wyndmoor, PA 19038, USA.
authors: Joseph E
authors: JE
authors: Sites
authors: United States Department of Agriculture, Eastern Regional Research Center, 600 Mermaid Lane, Wyndmoor, PA 19038, USA.
authors: Glenn
authors: G
authors: Boyd
authors: National College of Natural Medicine, 014 SE Porter St., Portland, OR 97201, USA.
authors: Alison
authors: A
authors: Lacombe
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry; D002139:Caliciviridae / Q000187:drug effects*; D015169:Colony Count, Microbial; D019453:Escherichia coli O157 / Q000187:drug effects*; D005506:Food Contamination; D019649:Food Industry; D005516:Food Microbiology; D018545:Lactuca / Q000382:microbiology*; D008089:Listeria monocytogenes / Q000187:drug effects*; D010100:Oxygen / Q000737:chemistry; D018515:Plant Leaves / Q000382:microbiology; D058626:Plasma Gases / Q000494:pharmacology; D010969:Plastics; D012475:Salmonella / Q000187:drug effects*
chemical_list: D000890:Anti-Infective Agents; D058626:Plasma Gases; D010969:Plastics; D010100:Oxygen
keywords: Cold plasma; E. coli O157:H7; L. monocytogenes; Romaine lettuce; Salmonella; Tulane virus