Recovery of Salmonella from Steam and Ethylene Oxide-Treated Spices Using Supplemented Agar with Overlay

dc.contributor.authorCaver, Christopher Brandenen
dc.contributor.committeechairWilliams, Robert C.en
dc.contributor.committeememberPonder, Monica A.en
dc.contributor.committeememberEifert, Joseph D.en
dc.contributor.departmentFood Science and Technologyen
dc.date.accessioned2017-12-29T07:01:27Zen
dc.date.available2017-12-29T07:01:27Zen
dc.date.issued2016-07-06en
dc.description.abstractSalmonella enterica has been associated with several outbreaks due to consumption of low water activity foods including spices. Consequently, to improve microbiological quality, spices are commonly treated before ultimately reaching consumers. These processes may result in sub-lethal injury to cells, which can lead to an underestimation of microbial populations when plating on selective media. Sub-lethally injured cells are difficult to enumerate due to reduced ability to grow on selective microbiological media. Poor recovery of sub-lethally-injured cells may obscure process validation results and lead to overestimation of process effect. Therefore, this work was performed to determine the influence of agar overlay and media supplementation methods on the recovery of Salmonella from steam and ethylene oxide treated peppercorns and cumin seeds. Traditional agar overlay allowed recovery of significantly more Salmonella (p < 0.05) from inoculated peppercorns treated with steam (65.5C, 15 sec.) than selective media (XLT4) or solid agar overlay. Additional supplementation of the TSA base to contain 3,3'-thiodipropionic acid further improved Salmonella recovery from steam treated peppercorns (p < 0.05). For peppercorns and cumin seeds subjected to ethylene oxide, neither sodium pyruvate + yeast extract, 3,3'-thiodipropionic acid, glycerophosphate, ATP, nor magnesium enhanced recovery compared to overlay alone but both methods recovered significantly higher numbers than XLT-4 alone (p < 0.05) for both cumin seeds and peppercorns.en
dc.description.degreeMaster of Science in Life Sciencesen
dc.format.mediumETDen
dc.identifier.othervt_gsexam:7454en
dc.identifier.urihttp://hdl.handle.net/10919/81456en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectSalmonellaen
dc.subjectrecoveryen
dc.subjectlow water activityen
dc.subjectspicesen
dc.subjectsteamen
dc.subjectethylene oxideen
dc.titleRecovery of Salmonella from Steam and Ethylene Oxide-Treated Spices Using Supplemented Agar with Overlayen
dc.typeThesisen
thesis.degree.disciplineFood Science and Technologyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Science in Life Sciencesen

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