Show simple item record

dc.contributor.advisorHardin, Margaret D.en_US
dc.contributor.advisorCastillo, Alejandroen_US
dc.creatorVillarreal Silva, Marianaen_US
dc.date.accessioned2011-10-21T22:03:32Zen_US
dc.date.accessioned2011-10-22T07:13:59Z
dc.date.available2011-10-21T22:03:32Zen_US
dc.date.available2011-10-22T07:13:59Z
dc.date.created2010-08en_US
dc.date.issued2011-10-21en_US
dc.date.submittedAugust 2010en_US
dc.identifier.urihttp://hdl.handle.net/1969.1/ETD-TAMU-2010-08-8542en_US
dc.description.abstractThe beef industry has made tremendous strides in reducing pathogen contamination on carcasses. Multiple antimicrobial interventions have been validated for their use during harvesting. Information in regards to cross-contamination with pathogens in the post-harvest environment is limited. Surrogate microorganisms for enteric pathogens are commonly used to validate antimicrobial interventions and might allow for the simulation of cross-contamination through the post-harvest environment. The purpose of this study was to determine how the post-harvest environment impacts the direct and indirect transmission of pathogens. This was achieved by using fluorescent protein-marked surrogate strains of Escherichia coli O157:H7 and Salmonella spp. from inoculated carcasses to the adjacent ones and to the equipment and facility in three different abattoirs. Thirteen hide-on carcasses were inoculated using a gelatin-based slurry containing three nonpathogenic fluorescent protein-marked strains of E. coli biotype I. In order to determine direct and indirect cross-contamination, inoculated and adjacent carcasses were sampled (300 cm2) during the harvesting process at different stages: after hide opening (AHO), prior to evisceration (PE), after evisceration (AE), after splitting (AS), and after final intervention (AFI). Environmental samples consisting of the floor, walls, and air were tested as well as personal equipment including gloves, boots, and aprons. Equipment including hand knives, air knives, meat hooks, hide puller and split saw were also sampled. Results showed evidence of cross-contamination between inoculated carcasses and the adjacent non-inoculated ones for all abattoirs. Although this occurred in all abattoirs, surrogate counts on carcasses were below detectable levels (<1.4 log CFU/cm2) after antimicrobial interventions. Surrogates were found in low levels for all environmental samples. However surrogate counts from equipment such as knives, split saws, meat hooks, and hide puller were more frequently detected (15 percent) than those found on the floor, air and walls samples (10 percent). In the case of aprons, boots, and gloves, the prevalence of countable surrogate samples was 7 percent.en_US
dc.format.mimetypeapplication/pdfen_US
dc.language.isoen_USen_US
dc.subjectEscherichia coli O157:H7en_US
dc.subjectSalmonellaen_US
dc.subjectsurrogateen_US
dc.subjectpathogenen_US
dc.subjectbeefen_US
dc.subjectcontaminationen_US
dc.titleSimulation of Contamination Through the Post-Harvest Environment Using Surrogate Organismsen_US
dc.typeThesisen
thesis.degree.departmentAnimal Scienceen_US
thesis.degree.disciplineFood Science and Technologyen_US
thesis.degree.grantorTexas A&M Universityen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelMastersen_US
dc.contributor.committeeMemberMiller, Rhonda K.en_US
dc.type.genrethesisen_US
dc.type.materialtexten_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record