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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Microbiological analysis of bacterial pathogens in poultry feeds and water resources in Blouberg Poultry Value Chain Project, Limpopo Province, South Africa

Ngwenya, Lloyd January 2019 (has links)
Thesis (M.Sc. Agriculture (Animal Production)) -- University of Limpopo, 2019 / Poultry is a good source of animal protein for many households due to its affordability. However, it is prone to bacterial infections which can be passed on to consumers, hence chickens that are reared without constant health checks present a potential health threat to humans. The objective of the study was to identify the zoonotic bacterial pathogens in poultry feeds and water resources in Blouberg poultry value chain project. A total of 88 samples comprising of 14 feed samples, 14 water samples, 60 mouth and rectal swab samples were collected from the farms. The samples were screened for the presence of Escherichia coli, Salmonella spp. and Shigella spp. through selective cultivation. Only coliforms and the dominant isolates were identified as Escherichia coli, Klebsiella spp., and Enterobacter spp., Salmonella and Shigella spp. were not detected in all the samples. E. coli strains that were isolated from the water sources and mouth and rectal swabs of the chickens showed a significant resistance to gentamycin, neomycin, penicillin, streptomycin, tetracycline, erythromycin, nalidixic acid, ciprofloxacin and ampicillin (p<0.05). Klebsiella pneumoniae showed resistance to neomycin; penicillin; erythromycin (p<0.05) while K. oxytoca and E. absuriae showed similar antibiotic resistance profile as penicillin, erythromycin, nalidixic acid and ampicillin. E. coli and K. pneumonia are mostly implicated in poultry disease outbreaks and they are enteric pathogens in humans as well. The presence of pathogens in poultry presents a great risk of secondary infection in humans and this will lead to socio-economic problems for the affected communities. The information generated in this study will guide the relevant stakeholders who handle poultry feeds and water resources in following good management practices. 1 / National Research Foundation (NRF)
2

The food safety knowledge and microbial hazards awareness of consumers of ready-to-eat street-vended foods and their exposure to microbiological hazard

Asiegbu, Chioma Vivian 14 October 2016 (has links)
In many countries, the authorities face extreme difficulties in monitoring and ensuring that food sold on the street is safe, that is, fit for human consumption. This is particularly the case in urban areas, where people buy food on the street because it is readily available and relatively inexpensive. The objective of this study was to determine the food safety knowledge and microbial hazard awareness of street food consumers, and to assess the bacteriological quality of selected ready-to-eat foods sold by street vendors in the Johannesburg municipality. A cross-sectional survey study was conducted and a total of 402 respondents who buy and consume street-vended foods were randomly selected at various street food vending locations. A total of 315 various street-vended samples were purchased from randomly selected street food vendors at different vending locations in Johannesburg metropolis, in order to investigate the bacteriological quality of street-vended foods. Results of the bacteriological analysis revealed that total aerobic counts ranged from 0.3*102 - 0.4*105 cfu/g in cereals and grain-based foods; 0.4*102 - 0.5*105 cfu/g in meat-, dairy- and fish-based foods and 0.7*102 - 0.9*104 cfu/g in fruit- and vegetable-based foods. None of the food samples tested positive for Salmonella spp and Staphylococcus aureus. Results of the survey showed that the majority of respondents were black males younger than 35 years. Individuals of different gender, race, level of education and monthly income groups significantly (p<0.05) differed in their responses regarding the frequency of purchasing and confidence in the safety of street-vended food. Better taste followed closely by affordability and accessibility were the most cited reasons for purchasing street-vended food / Life and Consumer Sciences / M. Sc. (Life Sciences)
3

Genomic characterisation and antimicrobial resistance profiles of Listeria monocytogenes isolated from pig farms

Masemola, Puseletso Maselepe 07 1900 (has links)
Listeria monocytogenes is a zoonotic foodborne pathogen, transmissible from the natural agricultural environment to animals and humans. In recent years, the pig production industry has experienced a series of monetary losses as a result of the L. monocytogenes outbreak which threatened the economy of South Africa. This outbreak also had a detrimental effect on the health system of the country. In South Africa however, there is limited information regarding the genomic diversity of L. monocytogenes. Therefore, an overview of the genomic diversity of L. monocytogenes strains circulating at different levels of the pork production chain needs to be determined so as to be able to identify routes of contamination of the pathogen and thus improve meat safety. This study was aimed to determine the antimicrobial resistance patterns and population structure of L. monocytogenes isolated from pig farms in South Africa. Based on wholegenome sequence analysis, 77 isolates of L. monocytogenes were differentiated into four molecular serogroups with IIa (45.5%) being the most prevalent followed by IIc (26.0%), IVb (22.1%) and IIb (6.5%). Overall, 11 clonal complexes (CCs) were identified in this study, with the predominance being observed from; CC204 (23.4%), CC1 (19.5%) and CC2 (16.9%). Genetic elements associated with biocide, antimicrobial and heavy metal resistance were noted in 24.7 %, 48% and 11.7% of the isolates, respectively. Listeria pathogenicity island 1 and 3 that harbored clusters of virulence genes were present in 38.8% of the isolates. Five different plasmids were found in 68.9% of the isolates. This study has given baseline data on the genomic diversity of L. monocytogenes strains that are associated with biocides, heavy metal and antibiotics resistance genes. The data again demonstrated the genotypes of L. monocytogenes that are prone to contaminate the farm environment and possibly cause diseases in animals and humans. / Life and Consumer Sciences / M. Sc. (Life Sciences)
4

Food safety and quality assurance measures of the National School Nutrition Programme in Mpumalanga Province, South Africa

Sibanyoni, July Johannes 05 1900 (has links)
Foodborne diseases are a major challenge to school feeding programmes because inadequate food safety knowledge and skills of staff can result in unsafe food handling practices and cross-contamination, thus causing foodborne disease outbreaks. The aim of this study was to investigate the food safety and quality assurance measures of the National School Nutrition Programme (NSNP) in Mpumalanga Province, South Africa. The research design was cross-sectional quantitative in nature. A total of 300 NSNP food service managers/coordinators and 440 food handlers were selected to participate in the study. Data collection was by means of a selfadministered structured questionnaire and 192 food contact surface swap samples from 32 primary and secondary public schools.The majority of schools offering NSNP meals were located in informal settlements and most were found to lack basic resources such as electricity and potable tap water in their kitchens. 93% of food handlers did not know about Hazard Analysis Critical Control Point (HACCP). The NSNP food service managers in some schools, especially in schools located in rural settlements, were found to have little knowledge or awareness of HACCP. No school was found to have implemented the HACCP, and only a few staff had received food safety training. Inadequate food safety knowledge was worst in schools located in informal settlements due to a lack of training. Up to 60% of food handlers did not know the correct procedure for washing a cutting board after it had been used. In addition, just over 95% of the food handlers did not know how to sanitise utensils and cutting surfaces after cutting up raw meat. The lack of hygiene was confirmed by the presence of Listeria monocytogenes, Staphylococcus aureus, E.coli 015:H7, Salmonella and Shigella species on food contact surfaces. A total of 22 different bacteria genera were identified. It is essential to monitor NSNP kitchen hygiene practice to ensure the minimal contamination of food products and newly recruited food handlers should be trained on food handling practice and principles to ensure the safety of prepared food for school children. / Health Studies / D. Phil. (Consumer Science)

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