Theses and Dissertations Collection
Permanent URI for this collectionhttp://10.10.97.169:4000/handle/123456789/4448
Browse
Recent Submissions
Item Socio-economic assessment of agricultural commercialisation of indigeneous african vegetables: a case study of african eggplant in Arumeru district(Sokoine University of Agriculture, 2008) Kalugira E. GA study aimed at assessing the socio-economic impact of household’s participation in commercialization African eggplant (solarium aethiopicum) was carried out in four villages in Arumeru district in Tanzania. The study determined the existing extent of commercialization of African eggplant by households, determined and compared at different levels of commercialization the household members’ time allocation, income levels and ownership by gender, as well as land resource allocation for different crops. Data were collected by structured questionnaire for individual farmers supplemented by interview checklists for focus group. SPSS computer programme was used for data analysis. The results showed that: African eggplant growers had significantly higher extents commercialization than non growers. Time spent by household’s members, income levels and women’s control of income was also higher in African eggplant growers. The average land allocation for food crops was 0.76 hectares and 0.70 hectares for African eggplant growers and non-growers respectively which is insignificantly different between the two farmers’ categories. Time in hours per day spent by family members for African eggplant growers was 7.64 while for non-growers was 5.2. Moreover, total annual income in Tanzanian shillings (TShs) of African eggplant growers was 2 449 617 compared to 2 030 767 for non-growers. In case of women’s control of income, there was a slight difference between the two categories in which for African eggplant growers decision making by both husband and wife was higher. The following policy implications have been raised: Commercialization of African eggplant should be enhanced notably through improving technologies. Participation of women should be safeguarded by increased access of women to credit for the short term financing of cash crop productive inputs. Acquiring land for production of African eggplant through renting instead of using land which has been used for production of food crops should be maintained.Item Detection of proteolysis in milk by four selected methods(The University of Reading, 2009) Chove, Lucy MlipanoSensitive methods that are currently used to monitor proteolysis are limited due to their high cost and lack of standardisation for quality assurance in the various dairy laboratories. In this study, four methods, trinitrobenzene sulphonic acid (TNBS), reverse phase high pressure liquid chromatography (RP-HPLC), gel electrophoresis and fluorescamine, were selected to determine their suitability for the detection of proteolysis in milk by added trypsin, plasmin, Pseudomonas fluorescens NCIMB 701274 (414) and Pseudomonas fluorescens NCIMB 702085 (416) and Bacillus licheniformis enzymes. Raw, pasteurised and UHT milk used to study proteolysis were analysed by the four methods. Pseudomonas fluorescens enzyme was extracted in this study since commercial enzymes are not available. All four methods confirmed that Pseudomonas fluorescens 416 was more proteolytic than Pseudomonas fluorescens 414. Dialysis was effective in the purification of Pseudomonas fluorescens (Ps. fl.) enzymes increasing the detection limit for the fluorescamine method, which had a low upper detection limit. Prominent peaks by RP-HPLC were shown to occur between 20-30 min for Pseudomonas fluorescens but 20-25 min for Bacillus licheniformis. RP-HPLC confirmed a peptide peak at 35 min in pH 4.6 soluble extract, which was absent in 6% TCA soluble extract, was from plasmin. Casein breakdown profiles by gel electrophoresis confirmed preference for 0-casein degradation over a and K-caseins by both Ps. fl. and B. licheniformis. Comparison of raw and pasteurised milk (72, 85 and 90°C for 15 s) revealed that pasteurisation was insufficient to inactivate plasmin inhibitors. The pH 4.6 and 6% TCA soluble extracts of UHT skim milk with added trypsin or plasmin showed high correlations (R2 > 0.93) by the TNBS, fluorescamine and RP-HPLC methods, confirming increased proteolysis during storage. Gel electrophoresis showed that breakdown products from trypsin were similar to plasmin although the former caused more extensive proteolysis than the latter due to higher enzyme activity, y-caseins, formed as a result of P-casein degradation disappeared (1484 and 742 BAEE units of added trypsin on days 3 and 7) due to extensive proteolysis. This finding had not previously been reported. Milk processed at high temperatures (110, 120, 130 and 142°C for 2 s) had lower proteolytic activities than raw milk and milk heated at 85°C implying inactivation of plasmin at temperatures of 110°C and above. This was observed in all the methods assessed. The TNBS method was recommended on the basis of its accuracy, reliability, simplicity and cost.Item Effects of Hexanal and Calcium Chloride Post-Harvest Treatments in Management of Fresh Mango (Mangifera indica) Quality(Springer, 2022-07) Baltazari, Anna; Mtui, Hosea D.; Mwatawala, Maulid W.; Chove, Lucy M.; Msogoya, Theodosy; Samwel, Jaspa; Paliyath, Gopinadhan; Subramanian, JayasankarAbstract Experiments were conducted at the Sokoine University of Agriculture to assess the effects of hexanal at (0.02%) (volume/volume) and calcium chloride (2%) (weight/volume), on post-harvest quality of mango (‘Palmer’ and ‘Apple’) under different storage conditions and durations. A three factors factorial experiment was used for each variety and replicated six times. The fruits were stored at ambient temperature (28 ± 2 °C) or reduced temperatures (18 ± 2 °C) storage conditions. Data included physiological weight loss (PWL), fruit firmness, total soluble solids (TSS), titrat- able acidity (TA), TSS/TA ratio, vitamin C, total flavonoids, reducing sugar and total sugars which was collected at 0, 4, 8 and 12 days after harvest. Results indicated that hexanal and calcium chloride significantly (p \ 0.001) reduced mango PWL and improved fruit firmness and TSS of both varieties compared to untreated fruits. Hexanal-treated fruits maintained high vitamin C, total flavonoids, total and reducing sugars irrespective of the storage conditions. Vitamin C and total flavonoids of mango fruits decreased with storage time, whereas total and reducing sugar contents increased with storage time. Both treatments maintained physico-chemical qualities of mango fruits, when stored under reduced temperature storage. Keywords; Physiological weight loss , Fruits firmness , Total soluble solids (TSS) , Titratable acidity (TA) ,TSS/TA ratio , Vitamin C , Flavonoids , Reducing sugar , Total sugarItem Status assessment and roadmap for improvement of food safety management systems in Africa: the case of Tanzania(Ghent University, 2015) Kussaga, Jamal BakariChapter 1 reviews various literature sources to provide an overview of the characteristics of food production sectors and the legal framework for food safety in Tanzania and tools used to measure performance of food safety management systems in the food industry'. It was found that Tanzania’s economy depends on agriculture: the manufacturing sector being largely agro-based and composed of micro- and small-scale enterprises. Majority of the food companies target the domestic market, especially, the dairy sector, while a few sectors like fish and horticulture produce for the export market, The current food laws and regulations are not yet adequate and well enforced to provide maximum protection to consumers. Besides, there is no national food safely policy as yet. Several institutions are involved in the food control without proper coordination and harmonisation of responsibilities. Furthermore, application of best practices and hazard analysis critical control point principles is not mandatory to food sectors serving the domestic market, limiting their use. This situation could contribute to food safety problems (including microbiological and chemical contamination and foodbome diseases) along the local and export food-value chains. Lastly, the chapter highlights also on the scientific tools, the food safety management system-diagnostic instrument and microbiological assessment scheme, developed by various researchers which were further used in this study. Chapter 2 provides a broad overview of the deficiencies and opportunities for improvement of food safety management systems of the African food industry-. Several literature sources were consulted to provide insights in food safety status of African food products, deficiencies of current food safety management systems, hurdles due to context characteristics and possible improvement strategies. Literature on microbiological and chemical safety of various products including fruits and vegetables, fish, meat, dairy and cereals were analysed to get insights in the current safety status of African food products. It was found that microbiological and chemical contamination exceeded the legal limits in most of the products targeted for export and local markets in the reviewed reports. Analysis of the deficiencies of food safety management systems in the reviewed reports revealed that the majority of core control and assurance activities were not yet developed, whereas for the ones developed (i.e. export oriented and large-scale companies), many were at basic level. The hurdles due to context characteristics in the reviewed reports were observed at government (due to poor legal framework for food safety), sector/branch organisations (lack of sector organisations and guidelines), market/rctail (inadequate food safety demands), and company levels (poor workforce quality, high dependency on chain actors, stakeholders’ conflicting demands) which affect performance of food safely management system in Africa. Lastly, measures for improvement were proposed at government (strengthen the national legal framework for food safety, formation of accreditation bodies and food safety education at all levels):sector/branch organisations (formation of sector guidelines and recommended use of traceability systems and auditable standards), inarkct/retail (private certification and price premiums, and expertise support) and company levels (technological innovations in hygienic design of equipment and facilities, set-up assurance activities, and creating supportive administrative structures). These measures were used as inputs for the development of generic roadmap for improvement of ESMS in Tanzanian food industry. Chapter 3 applied the food safety management system-diagnostic instrument to analyse the set-up and operation of food safety management system (control and assurance) activities in view of system output and context riskiness in 22 dairy processing companies in Tanzania. I lierarchical cluster analysis with the furthest neighbour and squared Euclidean method was used to analyse data; then, Kruskal Wallis Non Parametric test was applied to determine the significant differences among the clusters. Three clusters of companies di Hering in levels of set-up and operation of the ESMS and system output, but all operated in a similar moderate-risk context were identified. Cluster IA and IB had moderate system output, whereas cluster II had poor-moderate level. The microbiological assessment scheme was applied in one company to get deeper insight on the actual microbiological safety output of the current systems of dairy' processing companies. Six indicator micro-organisms for faecal hygiene {Escherichia coli), personal hygiene {Staphylococcus aureus), pathogens {Listeria monocytogenes. Salmonella spp.) and general process hygiene {Enterobacteriaceae and total viable counts) were analysed in nine critical sampling locations along the cultured milk production line. The actual microbiological assessment indicated contamination of products, food contact surfaces, and hands of the personnel with indicator microorganisms of faecal hygiene {Escherichia coli), personal hygiene {Staphylococcus aureus), and pathogens {Listeria monocytogenes) beyond the set limits. A two-stage intervention approach was proposed to enable commitment and sustainable improvement on the longer term. In the first stage, less demanding interventions (in terms of expertise/technology, financial and human resources) were recommended, whereas, high demanding measures (expensive and time consuming) were suggested in the second stage. Similarly, these interventions were used to develop the generic roadmap for improvement of food safety management systems in Tanzanian food industry. Chapter 4 assesses the food safety management system output in view of the current design and operation of food safety management system activities and context riskiness of these systems in order to identify the opportunities for improvement of the risk-based food safety management systems in the fishery sector. The diagnostic instrument was applied to assess the design and operation of core control and assurance activities in view of context riskiness and system output in 14 fish processing companies in Tanzania. Hierarchical cluster analysis with the furthest neighbour and squared Euclidean method revealed 2 clusters (cluster I and II) differing in system output but with similar level of food safety management systems (average level) and context riskiness (moderate-risk). In overall, cluster I companies had good system output while cluster II had moderate to good output. However, majority of the fish companies needed improvement of their FSMS to higher levels and reduce the context riskiness to assure good system output. A two-phase intervention approach was also proposed to implement the suggested measures in the fish companies. The less expensive interventions (like sanitation procedures, recruitment of skilled personnel on permanent basis) that can be implemented in the short- term are recommended for phase I. More expensive interventions (such as setting-up assurance activities, hygienic design of equipment and facilities, automation of the production process and sanitation) to be adopted in the longterm are proposed for phase II. These measures were also used as inputs to develop the generic roadmap for improvement of food safety management systems in Tanzanian food industry. Chapter 5 describes a combined assessment by the diagnostic instalment and microbiological assessment scheme to assess microbiological safety output of a risk-based food safely management system of a fish exporting company. The food safety management system diagnosis indicated average food safety management system activities which operated in moderate-risk context level but with good system output. The actual microbiological assessment involved 7 microbiological indicators for pathogens {Vibrio cholerae. Listeria monocytogenes and Salmonella spp.), faecal hygiene {Escherichia coli), personal hygiene {Staphylococcus aureus), and general process hygiene {Enterobacteriaceae and total viable counts) analysed in 12 critical sampling locations along the frozen Nile perch fillets processing line. Enterobacteriaceae and total viable counts exceeded regulatory limits in raw materials and working tables, whereas Staphylococcus aureus on operator's hands were beyond the general microbiological guidelines in the fish industry. Among the intervention measures for improvement included hygienic design, specific produclion/sanitation procedures and independent validation, process automation and change in personnel recruitment criteria. Likewise, the proposed measures were used to develop roadmap for improvement in the Tanzanian food industry. Chapter 6 involves a comparative assessment of the design and operation of food safety management system activities between the domestic oriented companies (dairy sector) and export oriented companies (fishery sector). The food safety management system-diagnosis data from Chapter 3 (dairy' sector) and Chapter 4 (fishery' sector) were evaluated to identify possible causes in the differences in the systems performance between the two sectors. Fish companies had average food safety management system and medium-good system output, while dairy' companies indicated basic-average food safety management systems and moderate system output. However, the food safety management systems of both sectors operated in moderate-risk context. This illustrates that both sectors need specific measures to improve their food safety management systems and reduce the risk-level of the context to guarantee food safely. The measures to reduce the level of context riskiness included putting high and specific requirements on operators’ competence level, describing all activities in standard operating procedures, and setting requirements on product use by major customers. The measures on the design and operation of food safely management systems involve use of industrial cooling facilities, hygienic design, strict raw material control, specific sanitation programmes, and analysis of critical control point. Dairy' companies need to set-up assurance activities including validation, verification, documentation, and record-keeping system. Enabling regulatory' environment (like national food safety policy, proper enforcement of laws and regulations) has to be established for the entire food industry (including the domestic market oriented sectors), to improve the design and operation of current core control and assurance activities and guarantee food safely. improvement technological infrastructure The measures to reduce the level of context riskiness included putting high and specific requirements on operators’ competence level, describing all activities in standard operating procedures, and setting requirements on product use by major customers. The measures on the design and operation of food safely management systems involve use of industrial cooling facilities, hygienic design, strict raw material control, specific sanitation programmes, and analysis of critical control point. Dairy' companies need to set-up assurance activities including validation, verification, documentation, and record-keeping system. Enabling regulatory' environment (like national food safety policy, proper enforcement of laws and regulations) has to be established for the entire food industry (including the domestic market oriented sectors), to improve the design and operation of current core control and assurance activities and guarantee food safely. Chapter 7 brings about the general discussion, roadmap for improvement of food safety management systems in the Tanzanian food industry', conclusions and recommendations for further research. Two concepts, the food quality relationship model and the improvement cycle were used to design the roadmap. The food quality relationship describes food quality as a function of food behaviour and human behaviour, food behaviour is dependent on dynamic product properties (food dynamics) and the applied technological conditions to stabilise the properties. Human behaviour is dependent of the dynamic individual decision-making of employees (human dynamics) and the applied administrative conditions to direct this behaviour (setting procedures and working practices in place). The improvement cycle involves three steps: (1) mapping the problem area (collecting information about the problem and documentation), (2) analysing the problem area (identification of causes and effects), and (3) redesigning (development and implementation of solutions). Based on the food quality relationship model, three levels of increasing efforts were defined; 1) changes in product and people behaviour, 2) changes in process conditions and administrative conditions, and 3) changes in the technological and organisational arrangements. Fish and dairy’ processing companies could use the generic roadmap to derive their company specific roadmaps towards more effective food safety management systems. Although this study was exclusively conducted in fish and dairy' sectors, the proposed generic measures for improvement could be also used by other food production sectors. However analysis of other sectors like fruits and vegetables, meat and poultry', and hospitality industry would identify specific deficiencies in their food safety management systems and tailor-made measures for each sector could be proposed to ensure supply of safe products for the entire nation. Moreover, this study focused on the techno-managerial approach of food safely management systems, however, the human factor, the so called ‘food safety climate or culture* could have an important role in the final performance of a food company. Therefore, future studies could take into consideration the food safety climate factor.Item Attitude towards learning food and nutrition subject and eating behaviours of ordinary level secondary school students in Dodoma region.(Sokoine University of Agriculture, 2022) Songo, Vashty NyabhigesoThe learning outcome of food and nutrition subject depends on attitude of the leaners towards the subject. In Tanzania, food and nutrition subject is taught in selected secondary schools at the ordinary level education and in even fewer schools at the advanced level. This study aimed to determine whether the attitudes towards learning food and nutrition subject influence eating behaviours of secondary school students. Data were collected in Dodoma region from three purposively selected secondary schools. The study involved 381 students who were randomly selected whereby 194 students opted and 187 did not opt to study food and nutrition subject. Nutrition information in the syllabus, teaching and learning materials were collected through documentary desk review. Students' attitudes towards studying food and nutrition subject and their eating behaviours were assessed through structured questionnaires that included, the dietary diversity component among others. Statistical Package for the Social Sciences (SPSS) Version 20 software was used to analyze descriptive and inferential statistics where t-test was conducted while qualitative data were analyzed by the text analytics program and interpreted according to the emerging themes. The study observed that syllabus had objectives that were relevant to the nutritional needs of the country. The subject specific textbooks were absent instead there were eleven (11) reference books used in all the surveyed schools. Those reference books had outdated nutrition information hence, not satisfactory to fulfil the need of the current syllabus and on address the existing problem of triple burden of malnutrition. Gender was found to influence choosing of the subject since mean attitude scores for males (M = 2.0154) which was half to that of females (M = 4.4995). Opting to study the subject influences eating behaviour significantly (p-value < 0.01). Among the 194 students who opted to study food and nutrition subject, 93% had proper eating behaviour because number of food groups eaten per day was five and above hence their dietary diversity score was above five (5). The students who had improper eating behaviour due to the fact that their diet consist less than five food groups was 7% hence their dietary diversity score was below five. The study concluded that students practice what was taught to improve their eating behaviour because students who opted for Food and Nutrition Subject had adequate dietary diversity in their diet compared to those who did not opt for studying the subject. The study recommends that, subject extracurricular activities on nutrition programs should be given to all students in order to emphasis and provide opportunity of improving their eating behaviour for their lifelong future benefits.Item Awareness of aflatoxin contamination and safety of maize along supply chain in Kondoa and Chemba districts in Dodoma, Tanzania(Sokoine University of Agriculture, 2022) Ndwata, Asha HamadMaize (Zea mays) is a staple food for the majority of people in Tanzania, which plays a key role in subsistence and as a cash crop among actors of the maize value chain. The study was conducted during the 2020–2021 cropping season in two districts, Kondoa and Chemba, in the Dodoma region of central Tanzania. The objectives were to assess stakeholders' awareness of aflatoxin contamination in maize (smallholder farmers, traders, and consumers), to assess post-harvest handling practices of maize among smallholder farmers, and to determine the current levels of aflatoxins B 1 contamination in maize. Structured questionnaires were used to collect the data. A cross-sectional survey was used in collecting primary data. A total of 380 respondents, including smallholder farmers, traders, and consumers from each ward, were selected. In addition, 90 maize samples (40 from smallholder farmers, 20 from traders, and 30 from consumers) were analyzed for aflatoxins using High-Performance Liquid Chromatography (HPLC). The results show about 56% of the smallholder farmers and 52% of the traders were aware of the contamination. However, the majority of the main stakeholder (consumer) was unaware of the contamination with aflatoxins (74%). Moreover, the result shows smallholder farmers had inadequate knowledge of best post-harvest practices and these were associated with post-harvest losses and the microbiological quality of maize. It was observed that the majority of smallholder farmers (75% ) used traditional post-harvest handling practices such as harvesting maize and placing it on the ground, storing maize in galleries, drying (on the ground); use of polypropylene bags as a storage facility. Few samples of the maize value chain were contaminated with AFB 1 and total aflatoxins. Furthermore, the result shows five-point six percent (5.6%) of collected samples were contaminated with aflatoxins B 1 , and 3.3% of the aflatoxins samples exceeded the European Union (EU) and Tanzania Bureau of Standards (TBS) regulatory limits for AFB 1 and were mainly collected from traders in Kondoa district. Extension workers should train farmers on effective post-harvest management practices of maize in order to minimize losses and improve the quality. In addition, efforts should be made to educate the general public, particularly consumers, about the dangers of aflatoxins contamination, and affordable techniques should be made available to maize farmers in the Kondoa and Chemba districts of Dodoma, Tanzania, in order to reduce grain losses and increase income and food security.Item Drying of paddyunder hermetic storage conditions in Burundi(Sokoine university of agriculture, 2022) Ahishakiye, DioniseThis study assessed the extent to which rice producers from Kidwebeziirrigation scheme could know their productivity loss during post-harvest activities and assessed the performance of drying and storing paddy in Grain Safe Dryer. To achieve these objectives, first simple random sampling was used to select 147 rice farmers in the study area. The collected data were subjected to analysis where output responsiveness with respect to each of the inputs, technical, allocation and economic efficiencies was estimated. Statistical Package for Social Sciences (SPSS) analysis was used to estimate the perception of paddy loss during post-harvest activities. The study further assessed factors affecting loss levels among rice producers. Grain Safe Dryers were installed to assess the performance during drying and storage of paddy. The study applied GENSTAT to analyse the data from using Grain Safe Dryer to dry and store paddy. Findings of this study reveal that the paddy lost during post-harvest activities were between 0 and 9%.Furthermore, the results show that the major factor affecting post-harvest losses in the study area was the material used in post-harvest activities. The study showed that the Grain Safe Dryer had high drying performance comparing to the sun dried paddy. Moisture contents of dried paddy were varied in sun drying and in the two Grain Safe Dryer units with the changes in atmospheric conditions. The initial moisture content was 25.3%, which decreased until it all reached 11.7% (in 19 days) in Grain Safe Dryers and 13.9% (in 3days) under sun drying. In case of germination percentage it was found to be higher (85.2%) in Grain Safe Dryer compared to sun drying (80.8%). Quality of rice after milling was found to be better (80%) in Grain Safe Dryer than sun drying (30%).On the other hand, seeds handled in Grain Safe Dryers gave higher germination rate and quality due to moisture content removed slowly during drying compared to sun drying. However, in terms of moisture removed, good quality, and germination percentage in Grain Safe Dryers were better compared to the sun dried paddy. However, it is recommended to carry more studies on Grain Safe Dryer to be assessed in different ecological zones before wider dissemination of the hermetic storage system for use as a dryer.