Saskatchewan has good growing conditions, much land and water resources, minimal pest pressure and the expertise necessary for growing high-quality commercial vegetables. Statistics show, however, that commercial vegetable production occupies a relatively small place in the agricultural economy of Saskatchewan. Saskatchewan production accounts for less than 10 per cent of the total provincial market for fresh vegetables, the other supplies of fresh vegetables marketed in Saskatchewan come from sources outside of the province and imports from the southern United States, Mexico, and other warm regions. The majority of Saskatchewan produced vegetables are sold through market gardens, farmers’ markets and consumer contract sales. In light of the increasing importance of fresh vegetable demand, examining the role of a new marketing organization in the province is important as it might bring about major realignment of the Saskatchewan fresh produce market. Recently, a project supported by the Agriculture Council of Saskatchewan Inc. (ACS) encouraged producers to organize themselves into picking zones and to work together to supply larger retail markets. The Grocery People (TGP) (a retailer) has agreed to purchase vegetables grown in Saskatchewan for their distribution centre in Saskatoon. This new organization, Prairie Fresh Food Corporation (PFFC), despite its numerous benefits, will test the farmer participants’ resolve to cooperate rather than proceed alone. This poses a real opportunity for producers to expand and develop the infrastructure required, as produce can be pooled. This study uses Transaction Cost, Agency and Monopolistic Competition theories to analyze the factors that hamper farmers from participating in contracts and taking advantage of these potential opportunities. It considers the advantages and barriers or potential challenges to wholesalers and retailers cooperating with this plan. In particular, an economic model of economies of scale through collective action is developed. The model assumes that small growers can access higher market share through collective action and achieving economies of scale. The results of personal interviews with eleven members of PFFC are presented and analyzed in a case study format. The case study analysis of PFFC reveals that the organization could provide positive benefits to its members in the early period of its establishment. The results show that the market share of the PFFC is still relatively small throughout the province, but its members expect it to expand in the future. The results suggest that high relative prices in the market and trust in the buyer have a positive effect on the probability of farmer participation in the project.

Irrigation water is perhaps the leading pre-harvest source of contamination of fresh vegetables in the world. In this thesis, the effect of source water from the Olifants River and the Wilge River on the bacterial quality of water in the Loskop Canal that they feed and also the subsequent contribution to the bacterial contamination of fresh vegetables was determined for a period of twelve months. Also effect of attachment time on the survival of Listeria monocytogenes and the effect of chlorine on L. monocytogenes attached to vegetables were determined. Finally, a step-wise logistic regression analysis was made to determine whether various predictor variables could be used to predict the occurrence of L. monocytogenes, Salmonella spp and intestinal Enterococcus in irrigation water and vegetables (i.e., cauliflower and broccoli). COD and turbidity were higher in the Olifants River and the Wilge River than in the Loskop Canal that they feed, according to the water guidelines set by the World Health Organisation (WHO) and the Republic of South Africa (RSA). The level of the COD and turbidity were significantly different in terms of the two rivers in comparison with the canal. Levels of faecal coliforms and Escherichia coli were also higher than the WHO standard. Staphyloccocus aureus, intestinal Enterococcus, Salmonella, L. monocytogenes were recovered from the two rivers and the canal. Apart from L. monocytogenes that was not recovered from cauliflower, all bacterial pathogens recovered from the surface water were recovered from the vegetables. This study also indicated that L. monocytogenes could attach to both surface and subsurface structures of both tomatoes and spinach within 30 min, and that even after 72 h, it still remained viable. It also indicated that chlorine treatment is more effective against surface L. monocytogenes compared with subsurface inoculated L. monocytogenes. Finally, the logistic regression analysis of the sampled data showed that COD was statistically reliable to indicate a high probability of L. monocytogenes, turbidity reliable to indicate a high probability of intestinal Enterococcus and faecal coliforms and coliforms reliable to indicate a high probability of Salmonella in irrigation water. Low aerobic colony count (ACC) was statistically significant for the prediction of the three pathogens on vegetables. / Thesis (PhD)--University of Pretoria, 2010. / Food Science / unrestricted

<p>While fresh vegetables (FVs) consumption is essential for public health, some high-profile outbreaks that cause severe illnesses are related to their consumption. To illustrate, the Center for Disease Control (CDC) and Prevention has estimated 48 million cases of foodborne illnesses in the U.S. per year; of them, about 46% are associated with FVs. The economic impact of food safety issues, estimated at $51 billion annually, is due to medical costs, productivity losses, and loss of consumer trust (Hoffman et al., 2021). </p> <p>The proliferation of risk mitigation methods (GAP, HACCP), food safety policies (FSMA), and information (labels, media, government) out in the market today, suggests that the way consumers understand food safety might be different from what policymakers, researchers, and retailers try to communicate. In addition, consumers' heterogeneous perceptions and beliefs can make communication with policymakers, researchers, and industry stakeholders ineffective when assessing food safety risks. </p> <p>Given the high demand for FVs and the communication mismatch with consumers, it is crucial to understand how consumers value food safety when purchasing FVs. This study clustered FVs consumers based on their food safety concerns. First, a Principal Component Analysis (PCA) identified the most relevant food safety dimensions. Later, using the food safety dimensions, this study segmented FVs consumers based on their food safety concerns. Finally, through a Multinomial Probit model (MNP), this study provided the main factors driving cluster membership.</p> <p>Our results suggest the existence of four segments of FVs consumers: “Worriers” (45% of our sample), who highly valued all the food safety characteristics when buying FVs. “Labelers” (20.3% of our sample) mainly valued attributes related to nutritional and environmental characteristics. “Pretty Vegetables” (17.3% of our sample) searched for the best and safest produce possible. Lastly, “DIYers” (17.3% of our sample) valued the least variables related to convenience in FVs. Finally, some of the main drivers of cluster membership were related to demographics, consumption, information sources, and perceptions about food safety of FVs consumers. These results can help policymakers, researchers, and retailers communicate food safety information more efficiently among different segments of consumers.</p>

La present tesi doctoral es centra en l'aplicació dels bacteris de l'àcid lactic (BAL) com a agents bioprotectors davant microorganismes patògens i deteriorants.Es van aïllar i seleccionar BAL de fruites i hortalisses fresques i es van assajar in vitro davant 5 microorganismes fitopatògens i 5 patògens humans.Es van realitzar assajos d'eficàcia en pomes Golden Delicious amb tots els aïllats enfront les infeccions causades pel fong Penicillium expansum. La soca més eficaç era Weissella cibaria TM128, que reduïa el diàmetre de les infeccions en un 50%.Les soques seleccionades es van assajar enfront els patògens Salmonella typhimurium, Escherichia coli i Listeria monocytogenes en enciams Iceberg i pomes Golden Delicious.Els BAL interferien eficientment amb el creixemet de S. typhimurium, and L. monocytogenes, però van mostrar poc efecte enfront E. coli.Finalment, es van realitzar assajos dosi-resposta amb les soques Leuconostoc mesenteroides CM135, CM160 and PM249 enfront L. monocytogenes. De totes les soques assajades, la soca CM160 va ser la més efectiva. / The present thesis focuses on the use of lactic acid bacteria as bioprotective cultures to inhibit pathogenic and spoilage microorganisms.Lactic acid bacteria were isolated and selected from fresh fruit and vegetables and tested in vitro against five plant pathogens and five human pathogen test bacteria.Efficacy trials with all the isolates were performed in Golden Delicious apples against the blue mould rot infections, caused by Penicillium expansum. The highest effectivity found in this assay was of about 50%, with strain Weissella cibaria TM128.Selected lactic acid bacteria were tested against Salmonella typhimurium, Escherichia coli and Listeria monocytogenes in Iceberg lettuce and Golden Delicious apples. Lactic acid bacteria interfered efficiently with the growth of S. typhimurium, and L. monocytogenes, but showed little effectivity over E. coli.Finally, dose-response assays were done with Leuconostoc mesenteroides strains CM135, CM160 and PM249 against L. monocytogenes.Among the three strains tested, strain CM160 showed the highest effectivity.