Salmonella Typhimurium Internalization in Fresh Produe under Plant Stress, and Inactivation of Internalized Salmonella Using Ultraviolet-C Irradiation and Chemical Disinfectants

Salmonella Typhimurium Internalization in Fresh Produe under Plant Stress, and Inactivation of Internalized Salmonella Using Ultraviolet-C Irradiation and Chemical Disinfectants

Bibliographic Details
Main Author: Ge, Chongtao
Language:English
Published: The Ohio State University / OhioLINK 2012
Subjects:
Food Science
Salmonella
internalization
fresh produce
extreme weather
phytovirus infection
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=osu1351625174
id ndltd-OhioLink-oai-etd.ohiolink.edu-osu1351625174
record_format oai_dc
collection NDLTD
language English
sources NDLTD
topic Food Science
Salmonella
internalization
fresh produce
extreme weather
phytovirus infection
spellingShingle Food Science
Salmonella
internalization
fresh produce
extreme weather
phytovirus infection
Ge, Chongtao
Salmonella Typhimurium Internalization in Fresh Produe under Plant Stress, and Inactivation of Internalized Salmonella Using Ultraviolet-C Irradiation and Chemical Disinfectants
author Ge, Chongtao
author_facet Ge, Chongtao
author_sort Ge, Chongtao
title Salmonella Typhimurium Internalization in Fresh Produe under Plant Stress, and Inactivation of Internalized Salmonella Using Ultraviolet-C Irradiation and Chemical Disinfectants
title_short Salmonella Typhimurium Internalization in Fresh Produe under Plant Stress, and Inactivation of Internalized Salmonella Using Ultraviolet-C Irradiation and Chemical Disinfectants
title_full Salmonella Typhimurium Internalization in Fresh Produe under Plant Stress, and Inactivation of Internalized Salmonella Using Ultraviolet-C Irradiation and Chemical Disinfectants
title_fullStr Salmonella Typhimurium Internalization in Fresh Produe under Plant Stress, and Inactivation of Internalized Salmonella Using Ultraviolet-C Irradiation and Chemical Disinfectants
title_full_unstemmed Salmonella Typhimurium Internalization in Fresh Produe under Plant Stress, and Inactivation of Internalized Salmonella Using Ultraviolet-C Irradiation and Chemical Disinfectants
title_sort salmonella typhimurium internalization in fresh produe under plant stress, and inactivation of internalized salmonella using ultraviolet-c irradiation and chemical disinfectants
publisher The Ohio State University / OhioLINK
publishDate 2012
url http://rave.ohiolink.edu/etdc/view?acc_num=osu1351625174
work_keys_str_mv AT gechongtao salmonellatyphimuriuminternalizationinfreshprodueunderplantstressandinactivationofinternalizedsalmonellausingultravioletcirradiationandchemicaldisinfectants
_version_ 1719431069133963264
spelling ndltd-OhioLink-oai-etd.ohiolink.edu-osu13516251742021-08-03T06:06:31Z Salmonella Typhimurium Internalization in Fresh Produe under Plant Stress, and Inactivation of Internalized Salmonella Using Ultraviolet-C Irradiation and Chemical Disinfectants Ge, Chongtao Food Science Salmonella internalization fresh produce extreme weather phytovirus infection Internalization of human pathogens is common in fresh produce.This threatens human health because the pathogens cannot be fully inactivated by conventional washing. This study examined the impact of water stress (abiotic factor) on the internalization of Salmonella Typhimurium in iceberg lettuce and green onion through soil and plant surface contamination during the pre-harvest stage. In addition, lettuce mosaic virus (LMV) infection (biotic factor) was introduced to determine whether the internalization via surface inoculation was affected in lettuce. Finally, different doses of ultraviolet-C radiation and their combination with chlorine/peracetic acid (PAA) were applied in an attempted to inactivate the internalized Salmonella. Salmonella was labeled with green fluorescence protein (GFP) and different concentrations of GFP-labeled Salmonella were inoculated into the rhizosphere-soil or sprayed on the leaf surface of the 4-week-old plants. LMV infection was only conducted in the surface-contaminated lettuce. The plants were irrigated with different volumes of water (drought, storm), collected after 2 days and cut into two parts (leaf, root/bottom) after surface disinfection to remove the attaching bacteria. Plate count and qPCR were used to determine the viable and total internalized Salmonella. The internalized Salmonella (via surface contamination) was also visualized using a laser scanning confocal microscope. This study discovered S. Typhimurium can disseminate throuought the entire plant after penetrating into the tissues through the roots or leaves. The viable Salmonella was detected in both parts of green onion, however, was only found in the lettuce leaves regardless of contamination method. However, once the lettuce was infected with LMV, the viable Salmonella showed up in the both parts. The water stress alone did not influence the internalization level in the lettuce when contaminated on the surface, or in the green onion using either contamination method. The viable Salmonella was only detectable in the lettuce when the soil was contaminated with 108 or 109 CFU/g-soil of bacteria. Additionally, the viable internalized Salmonella levels were generally higher under these conditions than if the lettuce were watered optimally. On the other hand, the extent of viable internalized Salmonella decreased in the leafy part of the LMV-infected lettuce under the water stress conditions when the lettuce was contaminated with 104 and 106 CFU/ml of Salmonella on the surface. For the disinfection study, Salmonella (108 CFU/ml) was spread on the lettuce surface and injected into the bottom part of green onion to generate bacterial internalization. The plants was collected after 2 days and subjected to surface cleaning before treatments. Significant reduction was achieved in the lettuce treated with high UV-C doses (150 450, 900 mJ/cm2) or UV-C-chlorine or -PAA, and in the green onion treated with with UV-C-chlorine or –PAA or UV-C doses of 150, 900 mJ/cm2. The plant firmness was well-maintained, although the lettuce changed color slightly when treated with 900 mJ/cm2 of UV-C. This is the first study assessing the risks of pathogen internalization in fresh produce under the impact of abiotic and biotic environmental factors. It also provides applicable research outcomes for developing practical methods to inactivate internalized pathogens for industry settings. 2012-12-18 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1351625174 http://rave.ohiolink.edu/etdc/view?acc_num=osu1351625174 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

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