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dc.contributor.authorWeller, Daniel Lowell
dc.date.accessioned2018-10-23T13:23:06Z
dc.date.available2018-10-23T13:23:06Z
dc.date.issued2018-05-30
dc.identifier.otherWeller_cornellgrad_0058F_10716
dc.identifier.otherhttp://dissertations.umi.com/cornellgrad:10716
dc.identifier.otherbibid: 10489531
dc.identifier.urihttps://hdl.handle.net/1813/59446
dc.description.abstractThe complexity of the global food supply chain, and the demands of a growing population for safe, sustainable food requires novel, holistic, and adaptive approaches to produce safety. However, food is not produced in a vacuum; farms are closely linked to surrounding environments, which can function as pathogen reservoirs as well as pathways for pathogen dispersal into fields. Thus, a comprehensive understanding of the ecological processes that drive the presence, dispersal and persistence of bacterial pathogens in agricultural environments is essential for the development of adaptive approaches to fresh produce safety. In the studies presented here, we employed several approaches to investigate the ecological processes associated with pathogen dispersal in and contamination of produce production environments at multiple scales. Specifically, these studies investigated (i) spatial and temporal risk factors associated with L. monocytogenes isolation at the farm, field and sub-field levels, and (ii) factors associated with the transfer of generic E. coli from contaminated wildlife feces to and survival on individual, preharvest produce items. We observed that foodborne pathogens are not uniformly present in agricultural environments, and that specific spatial (e.g., proximity to pasture) and temporal (e.g., time between a rain event and harvest) factors were associated with an increased likelihood of pathogen detection. Using this information, we validated geospatial models that predict when and where pathogen contamination of produce production environments is likely to occur. We were also able to identify specific management practices that were associated with pathogen contamination of preharvest produce. For example, irrigation water was found to be a key pathway for pathogen dispersal in agricultural environments. The transfer of bacteria from in-field contamination sources, such as wildlife feces, to preharvest produce during irrigation was significantly associated with the distance between the produce and the feces. Following contamination, bacteria were able to survive on in-field produce for >10 days. Die-off observed over these 10 days followed a biphasic pattern with more rapid die-off immediately following contamination (i.e., 0-106 hours post-contamination). Overall the findings of the studies reported here provide key data that can be used to develop targeted strategies for reducing the likelihood of preharvest produce contamination.
dc.language.isoen_US
dc.rightsAttribution-NonCommercial-ShareAlike 4.0 International*
dc.rights.urihttps://creativecommons.org/licenses/by-nc-sa/4.0/*
dc.subjectBacterial Die-off and Dispersal
dc.subjectGeospatial modeling
dc.subjectProduce safety
dc.subjectEpidemiology
dc.subjectFood science
dc.subjectListeria monocytogenes
dc.subjectMicrobiology
dc.subjectPredictive Modeling
dc.subjectEscherichia coli
dc.titlePATHOGENS, PRECIPITATION, POOP AND PRODUCE: THE ECOLOGY AND CONTROL OF FOODBORNE PATHOGENS IN PRODUCE PREHARVEST ENVIRONMENTS
dc.typedissertation or thesis
thesis.degree.disciplineFood Science and Technology
thesis.degree.grantorCornell University
thesis.degree.levelDoctor of Philosophy
thesis.degree.namePh. D., Food Science and Technology
dc.contributor.chairWiedmann, Martin
dc.contributor.committeeMemberMehta, Julia Leigh
dc.contributor.committeeMemberIvanek Miojevic, Renata
dcterms.licensehttps://hdl.handle.net/1813/59810
dc.identifier.doihttps://doi.org/10.7298/X44B2ZJG


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