|MIN, SEA CHEOL - SEOUL WOMEN'S UNIVERSITY|
|ROH, SI HYEON - SEOUL WOMEN'S UNIVERSITY|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/10/2016
Publication Date: 7/16/2016
Citation: Niemira, B.A., Min, S., Roh, S., Boyd, G., Sites, J.E. 2016. Dielectric barrier discharge atmospheric cold plasma treatments to inhibit foodborne pathogens and tulane virus in Romaine lettuce. Meeting Abstract. Volume 1:Page 1; IFT Annual Meeting, Chicago, Illinois; July 16-19, 2016.
Technical Abstract: Dielectric barrier discharge atmospheric cold plasma (ACP) treatment is a novel, promising antimicrobial method. Of particular interest is the potential for ACP as an in-package decontamination method for fresh produce. Such tools are highly desirable, as they minimize the possibility of post-processing contamination. The objectives were to 1) determine the effects of ACP treatment on the inhibition of E. coli O157:H7, Salmonella, L. monocytogenes, and Tulane virus (TV) inoculated on Romaine lettuce, and 2) establish the effects of combining ACP with moisture vaporization, modified atmospheric packaging (MAP), and post-treatment storage on the inhibition of microorganisms in lettuce. Romaine lettuce was inoculated with E. coli O157:H7, Salmonella, L. monocytogenes (approximately 6 log CFU/g lettuce), or TV (approximately 2 log PFU/g) and packaged in a petri dish (150 mm diameter) or a polyethylene pouch (152 ' 254 mm). Leaves were packaged with and without moisture vaporization inside package. A subset of pouch-packaged leaves were flushed with MAP composed of O2 at 5% or 10%, with the balance being N2. All of the various packaged lettuce samples were treated by ACP at 47.6 kV for 5 min. Treated packages were analyzed for the inhibition of microorganisms, either immediately or following post-treatment storage for 24 h at 4 degrees C. ACP treatment inhibited E. coli O157:H7, Salmonella, L. monocytogenes, and TV by 1.1 +/- 0.4, 0.4 +/- 0.3, 1.0 +/- 0.5 CFU/g, and 1.3 +/- 0.1 PFU/g, respectively, without environment modification with moisture and gas in packages. The inhibition of bacteria was not significantly affected by the type of lettuce packaging or moisture vaporization (P>0.05). Modifying gas composition inside package using the N2-O2 mixtures reduced the inhibition rates of E. coli O157:H7 and TV. Following storage, L. monocytogenes declined by an additional 0.4 log CFU/g, suggesting a sublethal injury. The results indicate that ACP in air effectively inactivated E. coli O157:H7, Salmonella, L. monocytogenes, and TV in lettuce. Of these, Salmonella was least sensitive to the ACP treatment. L. monocytogenes continued to decline in post-treatment cold storage. Reduced-oxygen MAP gas composition reduced the effectiveness of ACP. Both rigid and flexible conventional plastic packages were suitable for in-package decontamination of lettuce using ACP. Atmospheric cold plasma applied to packaged Romaine lettuce was effective against E. coli O157:H7, Salmonella, L. monocytogenes, and Tulane virus, a surrogate for human norovirus. Gas composition in the package is an important factor determining ACP treatment effectiveness in in-package decontamination. Both rigid and flexible types of conventional and commercial plastic packages can be used for packaging lettuce to be decontaminated by cold plasma.