Thesis (M.S.)--Ohio State University, 1973. / Includes bibliographical references (leaves 136-139). Available online via OhioLINK's ETD Center.

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine.

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Purpose: To compare the prevalence of school-lunch salad bars in Arizona and differences in implementation by rural vs. urban setting. Background•Individuals in rural settings are increasingly at risk for health disparities and experience a disproportionate burden of chronic conditions. •Fruit and vegetable (F&V) is linked with lower risk for chronic diseases like diabetes, heart disease, and obesity. •Young people do not meet the recommended servings of F&V. •Salad bars are a recommended method to increase F&V intake, however there is limited evidence of their effectiveness. No studies exist that examine implementation of salad bars in urban versus rural environments.

Verocytotoxigenic Escherichia coli (VTEC) is a major cause of diarrheal infections. It is increasingly associated with the consumption of fresh produce and responsible for several international outbreaks with severe sequelae. Quantitative risk assessment (QRA) aim to evaluate the risk of contamination, quantify uncertainties and identify potential mitigation steps. Current published QRA focus on post-harvest process steps without consideration of pre-harvest factors. This study aimed to identify preharvest knowledge gaps and quantify the potential for growth of VTEC in plant tissue prior to harvest. Risk factors were used to develop a QRA for VTEC O157:H7 in ready-to-eat (RTE) salad from farm-to-fork. Plant host metabolites were analysed by mass spectrometry and chromatography. Further plant and bacteria derived factors involved in pre-harvest colonisation were determined and implemented into a QRA. The burden of disease was estimated as the probability of illness by consuming RTE salad in the United Kingdom (UK). VTEC was shown to frequently internalise into lettuce and spinach to high concentrations. There, it can persist, evade surface decontamination and crosscontaminate equipment and produce during processing. The probability of illness was estimated to be 2.66 * 10-5 for lettuce and 1.51 * 10-5 for spinach. Internalisation was determined as the driving factor for 1820 illnesses per year in the UK associated with the consumption of lettuce and 950 with spinach, respectively. Mitigation steps had limited impact on internalised VTEC O157:H7 and mostly reduced external bacteria. Outputs from the QRA indicate the insufficiency of current mitigation steps to reduce internal VTEC O157:H7 and highlights the need for advanced decontamination procedures. The QRA tool can be used for the development of industrial guidelines in order to improve food safety in the UK and Europe.

Salate eignen sich gut für den Anbau im Haus- und Kleingarten. In der Broschüre werden sowohl Standardsorten als auch Wildsalate und seltene Gartensalate aus verschiedenen Pflanzenfamilien vorgestellt. Neben Hinweisen zu Aussaat, Pflanzung, Wasser- und Nährstoffbedarf sind Empfehlungen zur Fruchtfolge, zum Verfrühen und zur Eingliederung in die Mischkultur enthalten. Abgerundet wird die Broschüre durch eine Planungshilfe für den Salatanbau im Freiland.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 176-182). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 176-182). Also available on the Internet.

Thesis (M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographical references.

The fresh-cut produce industry has seen expansive growth in recent years, to meet consumer demand ready-to-eat (RTE) salads have included the use of non-traditional ingredients. Uncommon ingredients include beet greens, kale, broccoli stalk, and Brussels sprouts, since these ingredients have not historically been consumed raw, potential food safety issues should be reassessed. Current processing technologies include produce washes that can reduce microbial levels but do not eradicate all populations. The lack of a kill step in produce processing emphasizes the need to minimize pathogen contamination during production and growth during a product’s shelf life. Listeria monocytogenes, a leading cause of foodborne illness related deaths, continues to challenge the industry with recent outbreaks and recalls of fresh-cut produce. These events present the need to better understand L. monocytogenes growth potential in RTE produce during storage and distribution. Traditional salad greens have been researched extensively, however, limited knowledge is available on new inclusions. While temperature is known to strongly influence microbial growth, the effects of physical abuse during storage and distribution are unknown. The purpose of this study was to characterize L. innocua’s, a surrogate for L. monocytogenes, growth behavior in processed beet greens, kale, broccoli stalk, and Brussels sprouts when exposed to simulated physical and thermal abuses during storage and distribution. To evaluate L. innocua growth during storage and distribution produce samples were obtained from a local processor in retail packaging and surface inoculated. The samples were conditioned at 4℃ for 18h prior to being exposed to a series of physical abuses (compression, drop, and vibration) typical of storage and distribution. After abuse, produce was incubated at 4 or 8°C and sampled post-abuse through 16 and 11 days, respectively. Samples were enumerated for L. innocua, aerobic and psychrotrophic microorganisms, and lactic acid bacteria. To monitor growing conditions in each vegetable, product pH, water activity, and headspace (gas analysis), were observed at each time pull. The study found physical abuse had no significant effect on L. innocua, or microbiota growth regardless of vegetable or incubation temperature (P > 0.05). Vegetable intrinsic factors (pH, Aw, and headspace) did not seem to interfere in L. innocua or background microbiota growth during incubation. All vegetables supported L. innocua growth under 8℃. Growth of L. innocua was greatest in beet greens, followed by kale, broccoli stalk, and Brussels sprouts in descending order. Significant growth of L. innocua at 4 and 8ᵒC was seen on day 6 and 4 in beet greens, 11 and 6 in Brussels sprouts, 16 and 4 in kale, and 16 and 6 in broccoli stalk (P < 0.05). Overall, these results show the studied RTE vegetables can support L. monocytogenes growth during storage and distribution, especially under abusive temperatures, demonstrating the importance of prevention strategies during processing and refrigeration throughout RTE produce shelf life.

No description available.