Masters Degrees (DBMB)

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Browsing Masters Degrees (DBMB) by Advisor "Uzabakiriho, Jean Damascene"

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    An evaluation of food safety management and hygiene practices by local informal food vendors: A case study of Ekutu open market, Kuisebmund, Walvis Bay, Erongo region, Namibia
    (University of Namibia, 2025) Shiindi, Sally Johanna; Uzabakiriho, Jean Damascene
    This study evaluated food safety management and hygiene practices among local informal food vendors at Ekutu open market in Kuisebmund, Walvis Bay, Namibia. Although informal food vending plays an important role in food access for low-income communities, limited regulatory oversight poses food safety challenges. The research aimed to assess vendor’s food handling practices, food safety knowledge, cleaning & disinfection efficacy (270 swabs) and the microbiological quality 17 of ready-to-eat foods (rice, salads, soup, spinach, porridge, fish, meat), 16 uncooked foods (raw bovine meat, fish, chicken and dried products (mopane worms, spinach, meat, fish, flour, beans), fruit (1) and milk(3). The data was gathered using structured questionnaires and direct observations using a rapid food hygiene inspection tool. Majority of the vendors were female (81%) over the age of 42, with 58% lacking food vending licenses. Compliance with handwashing practices was high, though lapses were identified in areas such as food covering (68%) and water reuse for cleaning utensils (75%) non-compliances. Microbiological analyses for swabs showed high total viable colony counts on dining tables and cutting boards, averaging 2.79 log cfu/cm² and 2.30 log cfu/cm² respectively, even after cleaning. Food samples revealed microbial loads, exceeding safety thresholds. Escherichia coli was detected in cooked rice (4.58 log cfu/cm²) and on several food contact surfaces. Statistical analysis showed a significant decline in the average % cleaning & disinfection efficacy from 63% (morning) to 13.6% (afternoon), with significant variance by surface type (p<0.001). These findings underscore critical gaps in food safety, revealing associations between vendor food safety knowledge and practices, particularly in prevention of cross-contamination and temperature control. To address these risks, the study recommends standardizing cleaning protocols in informal food markets, enforcement of compulsory hygiene pre-requisites programs through systematic hygiene monitoring programs and implementation of continuous training programs tailored to the local contexts
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    Seed bacterization with plant growth-promoting endophytes: Impact on Okra productivity, nutraceuticals and antimicrobial properties
    (University of Namibia, 2025) Ginindza, Thembakazi; Uzabakiriho, Jean Damascene
    The growing challenges of population expansion, climate change, rising food costs, and unpredictable rainfall patterns have intensified the need for sustainable agricultural practices that boost crop productivity while minimising environmental impacts. One promising strategy involves the combined use of plant growth-promoting endophytic bacteria (PGPEB) with the environmentally friendly hydroponic technique to enhance plant growth and functional quality. This study investigated the influence of seed bacterization with three PGPEB strains, Kosakonia cowanii (KC), Bacillus licheniformis (BL), and Cupriavidus metallidurans (CM), previously isolated from Myrothamnus flabellifolius, on the productivity, nutraceutical accumulation, and antimicrobial activity of okra (Abelmoschus esculentus L. Moench) under hydroponic (Kratky method) conditions. Okra seeds were soaked in single and combined bacterial inocula, germinated under dark conditions, and cultivated in a randomised complete block design with three plants per pot, four replications, and eight treatments. Results revealed significant improvements (P < 0.001) in seed germination percentage and seedling vigour index among inoculated treatments compared to controls, with KC and CM demonstrating strong individual and synergistic effects. BL was notably more effective when used in combination with other bacteria. Furthermore, methanolic extracts of okra pods from bacterized plants exhibited enhanced nutraceutical properties, including elevated total phenolic content (TPC), antioxidant activity (up to 91% DPPH inhibition), and increased inhibition of α-amylase (92%) and αglucosidase (88%), key enzymes linked to diabetes management. Thin-layer chromatography confirmed the presence of carotenes, while polysaccharides were detected across all treatments. Antimicrobial assays revealed substantial activity against pathogens such as Mycobacterium avium, Salmonella typhi, Candida albicans, and Staphylococcus aureus, with the strongest effects observed in methanolic extracts of BL-CM consortia. These findings underscore the potential of PGPEB consortia as eco-friendly bio-stimulants to enhance okra seedling establishment, yield functional bioactive compounds, and contribute to sustainable agriculture and novel nutraceutical and antimicrobial development. Further exploration of PGPEB-based biofertilizers may offer solutions for addressing chronic diseases and rising antibiotic resistance
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    Synergetic antimicrobial activity of bioactive secondary metabolites from endophytic Fungi and actinobacteria associated with Cassia Abbreviata oli. Subsp. Beareana (Holmes) Brenan
    (University of Namibia, 2025) Sinvula, Calvin A.; Uzabakiriho, Jean Damascene
    This study was designed to investigate antimicrobial activities in both axenic and interkingdom microbial fermentations of fungal and bacteria strains associated with the roots of a medicinal plant Cassis abbreviata. A diverse range of microorganisms, including Streptomyces, Patulibacter, Nocardiopsis, Rhodococcus, Curtobacterium, Bacillus cereus, Aspergillus, Paecilomyces, Trichoderma, Curvularia, and Epicoccum, were isolated the roots of Cassis abbreviata. PKS-I and NRPS gene clusters were also amplified. Isolates possessing at least one of these biosynthetic genes exhibited activity against at least more than one of the tested pathogens. The ethyl acetate extracts antimicrobial potential from 21- and 28-days incubation was evaluated against Listeria monocytogenes, Mycobacterium avium, Staphylococcus aureus, Shigella sonnei, Salmonella typhi, Escherichia coli and Candida albicans using the disk diffusion method. Statistical analysis showed no significant difference in inhibition zones between the two culture techniques (p = 0.124). However, notable extracts emerged; the 28- days fermented axenic extracts of Bacillus cereus and Trichoderma longibrachiatum and their 21- days co-culture extract showed significant good result against all test pathogens (p= 0.00). T. longibrachiatum and the co-culture extracts demonstrated a significant broad-spectrum potential against all test pathogens, with the co-culture demonstrating the highest zones of inhibition. Moreover, B. cereus extract inhibited only bacterial indicator microorganisms. Secondary metabolites from T. longibrachiatum and the 21- days co-culture extracts of Bacillus cereus and Trichoderma longibrachiatum were confirmed with TLC, which revealed the presence of alkaloids, flavonoids and phenols. Additionally, terpenoids were detected in the coculture extract only. The synergistic effect of combining the co-culture extract of 21- day incubation of B. cereus and T. longibrachiatum with the antibiotic nitrofurantoin, ii was demonstrated. It was observed that the inhibitory effect of both nitrofurantoin and the co-culture extract on the pathogen reduced by eight-fold. These results indicate that the endophytic fungi and bacteria from the C. abbreviata could be a potential source for bioactive antimicrobial compounds