Attachment of bacteria to teflon and buna-n-rubber gasket materials

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dc.contributor.authorGaspar-Rolle, Maria Nelma Pintoen
dc.contributor.committeechairPierson, Mark D.en
dc.contributor.committeememberBishop, J. Russellen
dc.contributor.committeememberGrayson, Randolph Larryen
dc.contributor.committeememberEigel, William N. IIIen
dc.contributor.committeememberPalmer, James K.en
dc.contributor.departmentFood Science and Technologyen
dc.date.accessioned2014-03-14T21:21:00Zen
dc.date.adate2005-10-13en
dc.date.available2014-03-14T21:21:00Zen
dc.date.issued1991-02-15en
dc.date.rdate2005-10-13en
dc.date.sdate2005-10-13en
dc.description.abstractSurface analysis of buna-N-rubber and teflon was performed. Scanning electron microscopy was used to analyze the topography of both materials and x-ray microanalysis identified the elemental chemical composition of the polymers. Teflon was primarily a smooth surface with random irregular spots, while buna-N-rubber had a very rough topography with "caverns" and crevices spread over the surface. The x-ray microanalysis showed that there are no impurities on the surface of teflon; however, calcium, silicone and sulfur were present on the surface of buna-N-rubber. Water contact angle measurements indicated that buna-N-rubber was a more hydrophobic surface than teflon. Qualitative analysis of the attachment of Pseudomonas fragi A TCC 4973, Listeria monocytogenes Scott A and Bacillus cereus ATCC 11778 to buna-N-rubber and teflon was assessed by scanning electron microscopy. These bacteria readily attached to both surfaces. Pseudomonas fragi attached after 2 hours in the presence of this microoorganism and Bacillus cereus and Listeria monocytogenes attached at 12 and 24 hours, respectively. Quantitative analysis of the attachment of Pseudomonas fragi to both surfaces as affected by various milk fat concentrations and temperature, and the availability of nutrients (different dilutions of skim milk, casein, casein and lactose, and whey and lactose) was conducted. Attachment was assessed by impedance microbiology. Milk fat content did not play a significant role in the process of attachment of this organism to either type of surfaces; however, significantly greater numbers attached to buna-N-rubber than to teflon. Overall bacteria attached in higher numbers to both surfaces when grown at 21°C, compared to bacteria grown at 4°C. For buna-N-rubber, bacteria attached in significantly higher numbers when the concentration of nutrients was minimal, while for teflon, the results were, in most cases, opposite to these.en
dc.description.degreePh. D.en
dc.format.extentxiv, 105 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-10132005-152525en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-10132005-152525/en
dc.identifier.urihttp://hdl.handle.net/10919/39818en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V856_1991.G387.pdfen
dc.relation.isformatofOCLC# 23843981en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V856 1991.G387en
dc.subject.lcshFood contamination -- Researchen
dc.titleAttachment of bacteria to teflon and buna-n-rubber gasket materialsen
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineFood Science and Technologyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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