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dc.contributor.authorWu, Jianen
dc.date.accessioned2016-06-01T06:00:25Zen
dc.date.available2016-06-01T06:00:25Zen
dc.date.issued2014-12-08en
dc.identifier.othervt_gsexam:3992en
dc.identifier.urihttp://hdl.handle.net/10919/71302en
dc.description.abstractListeria monocytogenes, Vibrio parahaemolyticus and Morganella morganii are closely related to foodborne illnesses caused by the consumption of seafood and ready-to-eat (RTE) food. Traditional Chinese medicines (TCM) have been widely studied as complementary and alternative medicines, and many of them have been verified to have antimicrobial properties. The purpose of this research was to study antimicrobial effects of plant extracts as potential preservatives in seafood products and to identify the primary antimicrobial compounds in plant extracts. Four plants, Pomegranate peel (PP, Punica Granatum L.), Chinese gallnut (CG, Galla chinensis), forsythia fruit (FS, Forsythia suspensa) and Baikal skullcap root (BS, Scutellaria baicalensis) were ground and extracted with 70% methanol, respectively. The extracts were diluted at tested for antimicrobial activities on V. parahaemolyticus, L. monocytogenes and M. morganii both in agar diffusion assay using tryptic soy agar (TSA), and in microdilution assay using tryptic soy broth (TSB). Both CG and PP extracts, with concentrations no lower than 1 mg/ml, significantly inhibited both V. parahaemolyticus and L. monocytogenes (P<0.01) and reduced the bacterial population by up to 4 logs. No significant inhibition was observed with FS and BS extracts, except for BS at 5 mg/ml on V. parahaemolyticus. None of the extracts showed significant inhibition against M. morganii. The antibacterial activities of CG and PP 70% methanol extracts were tested in ground raw tuna and cooked tail-on shrimp. The extracts were mixed in tuna with final concentration at 1.7 mg/ml, and applied as soaking treatments (5 mg/ml) for shrimp. Both CG and PP extracts inhibited V. parahaemolyticus on both food matrices while only CG significantly inhibited L. monocytogenes. The 70% methanol crude extract of CG was analyzed by HPLC and LC-MS. Oligo-galloyl-O-glucose (nGG, n=1-10) are the major compounds in CG. The crude CG extract was fractionated using HPLC and the fractions were collected based on elution time and tested for their antimicrobial activities against V. parahaemolyticus and L. monocytogenes using agar diffusion methods. The fractions containing 3GG-8GG were the most active antimicrobials on both bacteria.en
dc.format.mediumETDen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectListeria monocytogenesen
dc.subjectVibrio parahaemolyticusen
dc.subjectGalla chinensisen
dc.subjectpomegranate peelen
dc.subjectforsythiaen
dc.subjectScutellaria baicalensisen
dc.subjectshrimpen
dc.subjecttunaen
dc.titleInhibiting Listeria monocytogenes, Vibrio parahaemolyticus and Morganella morganii with Aqueous Methanol Extracts of Punica granatum and Galla chinensisen
dc.typeDissertationen
dc.contributor.departmentFood Science and Technologyen
dc.description.degreePh. D.en
thesis.degree.namePh. D.en
thesis.degree.leveldoctoralen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.disciplineFood Science and Technologyen
dc.contributor.committeechairEifert, Joseph D.en
dc.contributor.committeechairJahncke, Michael L.en
dc.contributor.committeememberWelbaum, Gregory E.en
dc.contributor.committeememberO'Keefe, Sean F.en


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