Date of Graduation

7-2015

Document Type

Thesis

Degree Name

Master of Science in Food Science (MS)

Degree Level

Graduate

Department

Food Science

Advisor/Mentor

Ricke, Steven C.

Committee Member

Lewis, Jeffrey A.

Second Committee Member

Foley, Steven L.

Keywords

Biological sciences; Fixatives; Flow cytometry; Quantitative PCR; Shiga toxin; Toxin detection

Abstract

Certain pathogenic Escherichia coli known as Shiga toxin (Stx)-producing Escherichia coli (STEC) are commensals in cattle, and typically cause bloody diarrhea in humans once the Stx toxin is secreted in invaded intestinal epithelial cells. Infections with STEC cells can lead to hemolytic uremic syndrome, which is commonly associated with kidney failure. Several STEC serogroups have been declared adulterants in raw, non-intact ground meat, and future regulations could potentially lead to a higher number of STEC serogroup detection strategies for these pathogenic microorganisms. Microbiological research laboratories may benefit from formalin-fixed STEC cells for periodic (daily, weekly, monthly, among others) instrument validation/calibration by serving as a working set of known cell concentration samples and internal standard i.e. positive control. These cell concentrations may be used across laboratories in different geographical locations, within an individual laboratory, and across a broad range of detection assays (molecular as well as immuno-based). This thesis consists of three research parts: a comprehensive literature review that covers STEC incidence in foods and molecular detection techniques (chapter 1), a literature review that covers immuno-based detection strategies (chapter 2), and a research manuscript that involves the development of an internal standard and positive control with formalin-fixed STEC cells that can be used for a broad range of molecular as well immuno-based detection assays for instrument calibration and validation purposes (chapter 3).

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