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Introduction and Justification: Diarrheal disease is a leading cause of death in children in low- and moderate-income countries. Food, food waste, and water are all vehicles that can promote the spread of diarrheal disease-causing bacteria like Campylobacter, Salmonella enterica, and E. coli. Resistance to commonly used antibiotics is on the rise, making them difficult to manage. This study aimed to determine prevalence and antibiotic resistance profiles of Campylobacter, S. enterica, and E. coli isolated from food, food waste, and water samples obtained from the Chobe Region of Botswana. In addition, the survival of two common pathogens, E. coli and C. jejuni, on kale, a type of leafy green commonly consumed raw, was determined. Methods: Samples were collected from the Chobe region of Botswana in 2022 including water from the local river, food (produce, beef, pork, and poultry) from local vendors, and food scraps from the landfill. Food samples were enriched in the appropriate selective media: Brilliant Green Bile Broth for E. coli, Bolton Broth for Campylobacter, and Rappaport Vassiliadis Broth for S. enterica. Water samples were collected using modified USEPA methods1103.1 and 1604, E.coli isolation was performed by plating on RAPID E.coli2 agar and incubation at 37°C for 2h and 44°C for 16-22h. Campylobacter, S. enterica, and E. coli were isolated from meat, poultry, and water samples before being sent to Virginia Tech, while enriched bacterial pellets from the produce were shipped for screening and isolation at Virginia Tech. E.coli were confirmed by PCR detecting the phoA gene (all E. coli), and classified as pathogenic through screening for the eae (present in enterohemorrhagic and enteropathogenic E.coli), stx1 and stx2 (present in enterohemorrhagic E. coli) and est1b ( present in Enterotoxigenic E.coli) genes. Campylobacter isolates were confirmed using a genera-specific PCR while S. enterica isolates were confirmed using invA primers. These enrichment and primer sets were tested as part of a study to determine the survival of E. coli O157:H7 and C. jejuni on kale during a 21-day shelf life. E. coli and S. enterica isolates were subjected to antibiotic resistance testing using the Kirby-Bauer Disk Diffusion method. Results: Methods for detection of inoculated E. coli O157:H7 on kale indicated survival for the majority of the shelf-life (up to 19 d), in comparison, C. jejuni was undetectable by day 13 using enrichment and PCR or plating. From the Botswanan samples, E. coli was isolated from 20% of produce, 49% of meat, and 84.7% of water. Salmonella was only isolated from produce samples (2.4%, 7/294). Resistance was uncommon among the Salmonella isolates with only one isolate being resistant to chloramphenicol. No Campylobacter were isolated from the screened produce, meat, or food waste. E. coli resistant to 3 or more classes of antibiotics (MCR) were identified in 15.5% of produce, and 22.2% of meat isolates. Isolation of E. coli or Salmonella from meat was not associated with a particular food type. In contrast, isolation of E. coli was more common from certain types of vegetables and fruits. Antibiotic-resistant E. coli were isolated more commonly from beef, poultry, and pork than from produce. Multi-class resistant E. coli were isolated from fruits, greens, soil associated, and above ground associated vegetables, beef, and poultry. Water samples were collected from the same time period as the food samples. E. coli isolation, especially pathogens (based on eae presence) was more frequent from environmental water samples collected during the wet season compared to the dry season. Water samples collected during periods of increased rainfall were more likely to contain E. coli isolates, especially pathogens. S. enterica and Diarrheagenic E. coli isolates, especially MCR isolates, pose a significant risk of illness to consumers. Strategies to reduce the circulation of these pathogens in foods and water sources are needed. / Master of Science in Life Sciences / People can get sick with diarrheal diseases after consuming contaminated food and water. These illnesses are difficult to treat and control when the bacteria causing them are resistant to antibiotics. Campylobacter, Salmonella, and diarrheagenic E. coli are three types of bacteria that can cause illness from food and water. These illnesses disproportionately affect people, especially children, in low-and moderate-income countries like Botswana. Little is known about the prevalence of Campylobacter, Salmonella, and diarrheagenic Escherichia coli in Botswana. This study aimed to determine the prevalence of these microorganisms as well as how resistant they are to different types of antibiotics. Samples from produce, beef, poultry, pork, and recreational water sources were collected in the Chobe region of Botswana over the course of 2022. Food samples were collected from different vendors and food scraps were obtained from the landfill. E. coli and Salmonella were isolated out of meat and water samples in Botswana while produce samples were shipped as mixed cultures to Virginia Tech where E. coli, Salmonella, and Campylobacter isolation or confirmation was done. Once the target bacteria were isolated, their resistance to certain antibiotics was tested. Salmonella was only found in produce from samples collected during October-December. No Campylobacter was found from produce, meat, or food waste. More E. coli was isolated from fruit or vegetable food waste collected from the landfill than from produce bought at local vendors. E. coli was obtained from meat purchased from local vendors more often than samples from the landfill. E. coli was found more often in water when there was more rainfall. E. coli that causes illness was also more likely to be obtained during the wet seasons. Resistant E. coli that could not be killed by the screened antibiotics, were classified as multi-drug resistant when it was resistant to more than three antibiotics. Rainfall, season, and the food source influenced if E. coli isolates were likely to be multi-drug resistant. While more research is needed to determine how these bacteria are moving in the environment and gaining resistance to antibiotics, the findings of this study show they are present in the environment and require further research.

Commodity options add a new dimension to grain farmers’ marketing alternatives. Producers of pain can now effectively ensure themselves a floor price without the risk of production shortfalls resulting in losses due to overhedged positions. The purpose of this study was to determine optimum hedge levels using both commodity options and futures contracts and then compare the hedging tools given various location, crop mix, and levels of financial leverage. The study used portfolio theory where hedging strategies were simulated over time and minimum-variance hedge levels determined. Crop diversification and financial leverage were addressed using Quadratic Programming techniques. Selected strategies were tested over a new data set. Commodity options are superior to futures contracts as a hedging tool for early season hedges. This was particularly true for crops with highly variable yields. The results also indicate that commodity options are a viable alternative for reducing long-run income variation and that crop diversification reduced income variation but did not reduce the overall need to hedge. The study presented here is unique in a number of ways. Initially, very little if any published work is available on hedging pain with commodity options contracts. Secondly, the study addresses hedging strategies under the realm of production uncertainty. Finally, the study demonstrates there are E-V efficient alternatives to strict cash sales. / Ph. D. / incomplete_metadata

The growing popularity of farmers' markets coupled with a high percentage of produce-related foodborne outbreaks highlights the need for an emphasis on food safety within these markets to protect farmers, patrons and local economies. The number of farmers' markets registered in the United States has almost tripled in the last 15 years. Fresh produce constitutes the majority of food sold at farmers'markets. Between 1998 and 2008, raw produce accounted for almost half of the 4,589 foodborne illness outbreaks linked to a specific commodity. This research was conducted to identify practices at farmers' markets which may contribute to an increased risk of contamination, assess the microbial quality of produce sold at farmers' markets, as well as to develop a food safety management plan template for market managers to utilize to build their own food safety plan. Using an observational data collection method, risky food safety practices were identified at Southwest Virginia farmers' markets. While market managers and vendors in three of the five markets observed had formal food safety training, numerous risky food safety behaviors were still observed including temperature abuse, cross contamination opportunities, and poor personal hygiene and sanitation. Additionally, the microbial quality of produce from Southwest Virginia farmers' markets was compared to produce sold at retail using culture based microbiological plating and molecular methods. Total aerobic bacteria and coliforms were enumerated, and the presence of Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus and generic E. coli were determined. A significantly greater quantity of total aerobic bacteria was isolated from farmers' market leafy greens, onions and tomatoes when compared to a retail grocery store (P=0.0011, P=0.0395, and P<0.0001, respectively). Additionally, one or more target pathogen was isolated from 28 farmers' market samples and 16 retail grocery store samples. The observed risky food safety behaviors along with the bacterial data collected emphasize the need for a pathogen reduction focus on fresh produce not only at farmers' markets, but also with growers and other retail outlets. To help promote proper food safety practices at farmers' markets, a farmers' market food safety management plan (FSMP) template was developed to address the top five risk factors contributing to foodborne illness as identified by the Centers for Disease Control and Prevention (CDC). The FSMP was evaluated for practicality and feasibility through interviews with market mangers in North Carolina and Virginia. Most market managers (66.7%) agreed that the FSMP was practical for their market while only 33.3% agreed that they could implement the plan immediately. Revisions suggested to the FSMP will be made and it will be made available in Virginia and North Carolina in spring 2016. / Ph. D.

This study was based around the working hypothesis that an increase in the theoretical and empirical base of knowledge about electronic marketing will aid in determining its feasibility and in system design, implementation and evaluation. The specific objectives of this study were: 1) to build a theoretical base from which the broad issues of electronic marketing could be examined; 2) to conceptualize, articulate and illustrate the issues involved in determining the feasibility and design of an electronic marketing system; 3) to examine the costs of electronic marketing both theoretically and empirically; 4). to explore the relationships between price level and variability and electronic marketing; and 5) to demonstrate, theoretically and empirically, a means of evaluating an electronic marketing system. Experiences gained from participation in the design and implementation of the computerized trading system of Electronic Marketing Association, Inc. (EMA) as well as analysis of sales data generated by EMA's operating electronic marketing system were used in fulfilling the objectives. In developing a theoretical base from which to examine electronic marketing, the study first examined a theoretically ideal marketing system, followed by common shortcomings. Possible solutions to these marketing problems were then examined. Lastly, the theoretical implications of electronic marketing regarding both pricing and technical efficiency were discussed. The study concluded that electronic marketing has the theoretical potential to increase both technical and pricing efficiency. The study developed a conceptual framework for determining the feasibility, designing and implementing an electronic marketing system. Based on experiences with EMA's trading system, the study developed a generalized outline of a feasibility study for beginning a new computerized electronic marketing system and identified important factors in designing and implementing an electronic marketing system. The study repeatedly emphasized the importance of feasibility studies, and the design and implementation process to the future of electronic marketing. The costs of Eastern Lamb Producer Coop's (ELPC) computerized sales, which use EMA's system, were examined. From the estimated cost functions and the distribution of cost among participants, it was concluded that the computerized sales resulted in greater technical efficiency than teleauction sales. The study also analyzed the price received at ELPC computerized slaughter lamb sales. The price received was found to be significantly higher than either the regional or national slaughter lamb price. ELPC's computerized prices had a significant effect on the regional slaughter lamb price, whereas previous teleauction sales did not. ELPC price changes tended to lead regional price changes by a week. The study concluded that the computerized sales offered superior pricing efficiency when compared to conventional auction methods. The mirror-image survey technique was demonstrated as a tool for evaluating electronic marketing systems. Both an unsuccessful attempt to sell slaughter cattle over EMA's system and the successful ELPC lamb sales were examined. Finally, broad generalizations from the limited experience were cautioned against. 'However, insight was gained concerning electronic marketing. / Ph. D.

Master of Science

Thesis (MBA (Business Management))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: This research report is a comparative analysis of the pre-1996 marketing control board system and the post-1996 free market system in the fruit and vegetable industry in South Africa. The report investigates and discusses the advantages and disadvantages of both systems and their effect on the stakeholders of the industry. The control boards had both positive and negative effects on the producer within the fruit and vegetable industry. The free market system is currently also having an effect, both positive and negative, on the producer. In this research report these divergent effects are explored, the objective being to obtain a better understanding of their impact on the industry stakeholders. On reaching a clearer understanding, strategy recommendations have been designed and are presented for all producers operating within the fruit and vegetable industry. The fresh produce industry is large, with many stakeholders. The information potentially available is vast, but, given the fact that time was too limited to do a complete research study on the entire industry, it was decided to focus on four sectors of the industry, namely bananas, deciduous fruit, citrus and potatoes. To give the report more credibility in terms of the data acquired, a number of interviews were conducted with producers and producer organisation leaders, from whom first-hand, ground level information was obtained. In this research it was found, among other things, that in general there was an imbalance in both the producer and consumer surplus in South Africa. Despite regulation, the marketing control boards had, through the pooling of prices, provided benefits only to certain producers. This, in effect, meant that quality improvement was largely negated, as the return to the producer did not provide an incentive to produce a better quality product. Contrary to the control board system, the free market system provides industry stakeholders with many opportunities, while the role of producers is also evolving to incorporate aspects of marketing. Producers consider service excellence, and culture and diversity to be important. Furthermore, in terms of available channels for marketing, many producers view the fresh produce markets as a desirable means of marketing their produce, as these outlets are still considered to be the price-determining mechanism for the fresh produce industry. / AFRIKAANSE OPSOMMING: Hierdie navorsingsverslag is 'n vergelykende studie van die bemarkingsbeheerraadstelsel voor 1996 en die vryemarkstelsel ná 1996 in die vrugte- en groentebedryf in Suid-Afrika. Die verslag ondersoek en bespreek die voor- en nadele van albei stelsels en hul uitwerking op die bedryf se belangegroepe. Die beheerrade het ’n positiewe sowel as negatiewe uitwerking op die produsent in die vrugte- en groentebedryf gehad. Die vryemarkstelsel het tans ook ’n positiewe sowel as negatiewe uitwerking op die produsent. Hierdie uiteenlopende gevolge word in hierdie navorsingsverslag verken om só ’n beter begrip van die impak daarvan op die bedryf se belanghebbers te verkry. Strategie-aanbevelings is op grond van groter begrip ontwerp en aan produsente in die vrugte- en groentebedryf voorgelê. Varsprodukte is die grootste bedryf in vrugte- en groentebedryf, en daar is talle belangegroepe. Die inligtingsmoontlikhede is enorm, maar gegewe die feit dat tyd te beperk was om ’n volledige navorsingstudie van die hele bedryf te onderneem, is daar besluit om vier sektore te beklemtoon, naamlik piesangs, sagtevrugte, sitrus en aartappels. Om die verslag meer geloofwaardigheid te gee ten opsigte van die data wat verkry is, is ’n aantal onderhoude met produsente en die leiers van produsentorganisasies gevoer om eerstehandse, voetsoolvlakinligting te bekom. Die verslag het onder meer bevind dat daar oor die algemeen ’n wanbalans in die produsente- sowel as verbruikersurplus in Suid-Afrika is. Die bemarkingsbeheerrade het ondanks regulasie voordele slegs aan sekere produsente gebied deur die saampot van pryse. Dit het in werklikheid beteken dat gehalteverbetering grootliks ontken is omdat die opbrengs nie die produsent aangespoor het om die gehalte van hul produkte te verbeter nie. Die vryemarkstelsel bied, in teenstelling met die beheerraadstelsel, talle geleenthede aan die bedryf se belangegroepe terwyl die rol van produsente ook ontwikkel word om aspekte van bemarking te inkorporeer. Produsente beskou voortreflike diens, en kultuur en diversiteit as belangrik. Daarby beskou produsente die varsproduktemark, wat een van die beskikbare bemarkingskanale is, as ’n wenslike manier om hul produkte te bemark omdat dié afsetpunt steeds as die prysbepalende meganisme vir die varsproduktebedryf gesien word.

The work described in this thesis was aimed at understanding the reactions taking place on heating Y2O3:Eu3+ phosphor precursors in the nano particle size regime. Herein combustion syntheses to prepare nanometer sized crystallites of cubic Y2O3:Eu3+ using precursors containing sacrificial long chain alkylammonium cations (the fuel) are reported. Using this method it proved possible to produce cubic Y2O3:Eu3+ crystallites in the 20-70nm size range. The presence of CO2 bands in the infra red spectra of the surface of the cubic Y2O3:Eu3+ crystallites are also reported. These bands are identical in position to those found in [(Y, Eu)OHCO3.H2O], and are explained as arising from the spontaneous reaction of the surface of the nanometer sized particles of cubic Y2O3:Eu3+ with atmospheric CO2 and water vapour. This indicates that nanometer sized particles of cubic Y2O3:Eu3+ are thermodynamically unstable in the atmosphere and must be protected against such back reactions. This could be done with surface coatings. Precursors of the products were prepared from methanolic and ethanolic solutions and then these were fired at temperatures of 650 and 900°C. Products (samples) prepared at a temperature of 900°C were observed to be all white powders in colour. Under 254nm uv excitation the samples prepared at 650°C displayed a weak red luminescence which was in contrast to the strong red luminescence from the samples prepared at 900°C that is characteristic of the Eu3+ ion in cubic Y2O3. The strongest red luminescence comes from 1:3 material sample ratios prepared at 900°C. The understanding of the chemistry behind the reactions and the characterisation and properties of the products formed are the major aims of the work reported here.

published_or_final_version / Business Administration / Master / Master of Business Administration