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dc.contributor.advisorCisneros-Zevallos, Luis
dc.creatorTroya, Maria Rosa
dc.date.accessioned2006-08-16T19:09:49Z
dc.date.available2006-08-16T19:09:49Z
dc.date.created2003-05
dc.date.issued2006-08-16
dc.identifier.urihttp://hdl.handle.net/1969.1/3929
dc.description.abstractFactors that affect liquid chemical intervention methods of controlling pathogens on fresh-cut produce were investigated. The relationship between produce tissue structure (intercellular space, cell size, and cell distribution) and the sanitizing effectiveness of liquid chemical treatment was studied. Experiments determined if sanitizer contact with bacteria could be improved through the use of surfactants and different application methods (drop application method, negative pressure differential, and sonication). To test these factors, a model sanitizer, H2O2, and a model microorganism: Salmonella Typhimurium, along with various fresh-cut produce (apple, pear, carrot, and potato) were tested. Microscopic analysis revealed a very complicated pore structure consisting of irregular capillaries. S. Typhimurium was found to survive in all produce tested, and washing did not significantly reduced inoculated bacteria regardless of the bacterial incubation time or produce type. The results showed that a 3% H2O2 solution reduced S. Typhimurium in produce and the solutionÂ’s efficiency varied in the following descending order: potato>apple>carrot>pear. In seven min treatments, bacteria were reduced by 2.5 CFU/ml in potato, 2.3 CFU/ml in apple, 1.5 CFU/ml in carrot, and 0.7 CFU/ml in pear. There was no direct evidence on how intercellular space, its percentage or cellular distribution and shape affected efficiency, but some possibilites were discussed. The rate and extent of liquid penetration, and how varying pore diameter in each cell or air space prevent complete chemical treatment penetration were also analyzed. It was determined that bacterial density has a slight effect in bacterial reduction but this depends on type of produce inoculated. The use of surfactants did not improve bacterial reduction in either washing or chemical treatments, and neither did the use of drop application method or temperature differential. On the other hand, applying the chemical treatment with a surfactant while using a sonicator did improve the treatmentÂ’s efficiency. This thesis provides a number of factors to be considered when designing a chemical treatment and a guideline for further research in areas such as rate and extent of liquid chemical treatment penetration into fresh-cut produce.en
dc.format.extent1683266 bytesen
dc.format.mediumelectronicen
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherTexas A&M University
dc.subjectFoodborne Pathogensen
dc.subjectFresh-cut Produceen
dc.subjectHydrogen Peroxideen
dc.subjectAntimicrobial Treatmenten
dc.subjectSurfactanten
dc.titleImproving liquid chemical intervention methods to control pathogens on fresh-cut fruits and vegetablesen
dc.typeBooken
dc.typeThesisen
thesis.degree.departmentHorticultural Sciencesen
thesis.degree.disciplineFood Science and Technologyen
thesis.degree.grantorTexas A&M Universityen
thesis.degree.nameMaster of Scienceen
thesis.degree.levelMastersen
dc.contributor.committeeMemberAcuff, Gary
dc.contributor.committeeMemberRichter, Ronald
dc.type.genreElectronic Thesisen
dc.type.materialtexten
dc.format.digitalOriginborn digitalen


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