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Curcumin-based photosensitization inactivates aspergillus flavus and reduces aflatoxin B1 in maize kernels
No full textJournal of Food Microbiology 82 (2019), pp. 82–88Different methods have been applied in controlling contamination of foods and feeds by the carcinogenic fungal
toxin, aflatoxin, but nevertheless the problem remains pervasive in developing countries. Curcumin is a natural
polyphenolic compound from the spice turmeric (Curcuma longa L.) that has been identified as an efficient
photosensitiser for inactivation of Aspergillus flavus conidia. Curcumin mediated photoinactivation of A. flavus
has revealed the potential of this technology to be an effective method for reducing population density of the
aflatoxin-producing fungus in foods. This study demonstrates the influence of pH and temperature on efficiency
of photoinactivation of the fungus and how treating spore-contaminated maize kernels affects aflatoxin pro duction. The results show the efficiency of curcumin mediated photoinactivation of fungal conidia and hyphae
were not affected by temperatures between 15 and 35 °C or pH range of 1.5–9.0. The production of aflatoxin B1
was significantly lower (p < 0.05), with an average of 82.4 μg/kg as compared to up to 305.9 μg/kg observed in
untreated maize kept under similar conditions. The results of this study indicate that curcumin mediated pho tosensitization can potentially be applied under simple environmental conditions to achieve significant reduc tion of post-harvest contamination of aflatoxin B1 in maize
Consumer preference for novelty in processed foods: a developing country perspective
No full textResearch PaperPurpose – The paper aims to explore consumer preferences for novel and other quality attributes in processed
foods. It focuses on preferences for product origin, certification on food quality and standards and tradeoffs
between novelty (fortification and highly processed) and other quality attributes.
Design/methodology/approach – In total, 317 consumers were randomly selected at a high-end
supermarket and a traditional local market in Dar es Salaam, Tanzania. Stated and revealed preference
approaches were used to investigate their preferences for different attributes in processed foods. A
hypothetical choice experiment was used to assess consumer preference for six baby food attributes and the
tradeoffs between the attributes, while the revealed preference method included questions on consumer’s actual
processed food purchasing and consumption habits. In addition, consumers were asked a series of hierarchical
questions assessing the motivation underpinning their choices for different products attributes.
Findings – When making choices for processed food attributes, consumers are reluctant to choose novel
technologies and have a strong preference for natural, nutritious, tasty and quality processed food attributes.
However, they are willing to forego their preference for naturalness and to overcome their reluctance to trying
novel technologies when the novelty is embedded with such quality benefits as nutrition, but not so when the
embedded benefit is convenience. They are also willing to trade off their preference for nutrition for a sensory
taste. This suggests that micronutrient deficiencies can be reduced among women and children under five by
employing the appropriate strategies in processed food formulation. Further, the preference for product origin
highlights the opportunity for national brands to fill the gap created by the increasing demand for processed
foods in Tanzania.
Research limitations/implications – The study claims a developing country perspective but is only
representing consumers in one city in a developing country. However, this study speculates that consumers
with representative characteristics in such context are likely to behave the same. Furthermore, although this
study controlled for a hypothetical bias, having a hypothetical choice experiment with non-shoppers (non purchasers) could have triggered the hypothetical bias, making participants concentrate more on non-price
than price attributes.
Originality/value – The paper offers a developing country perspective on consumers’ preferences for novelty
in processed foods and tradeoffs with other quality attributes
Prenatal exposure to persistent organic pollutants in Northern Tanzania and their distribution between breast milk, maternal blood, placenta and cord blood. Environmental Research
No full textHuman exposure to persistent organic pollutants (POPs) begins during pregnancy and may cause
adverse health effects in the fetus or later in life. The present study aimed to assess prenatal POPs
exposure to Tanzanian infants and evaluate the distribution of POPs between breast milk, maternal
blood, placenta and cord blood. For assessment of prenatal exposure, 48 maternal blood samples
from Mount Meru Regional Referral Hospital (MMRRH), Arusha Tanzania, were analyzed for
organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), brominated flame retardants
(BFRs), dioxin-like (DL) activity and perfluorinated alkyl substances (PFASs). For evaluation of
POPs distribution between maternal/infant compartments, breast milk, placenta and cord blood
corresponding to the maternal blood were analyzed for OCPs, PCBs and BFRs. In maternal blood,
p,p ́- DDE was detected in 100% of the samples ranging between 29 and 1890 ng/g lipid weight
(lw). PCB-153 was the only PCB detected in maternal blood, with detection rate of 29% and
concentrations up to 116 ng/g lw. BDE-47 was detected in 65% of the maternal blood samples,
ranging between <LOD and 83.2 ng/g lw. DL activity was measured using Dioxin Responsive
CALUX® bioassay. The DL activity was above LOQ in 92% of the samples, ranging from <LOQ
to 114 pg CALUX TEQ/g lw. PFASs was dominated by PFOS and PFOA, however, the
concentrations were low (range ∑PFASs 0.18-3.14 ng/mL). p,p ́-DDE was detected in 100% of the
breast milk, placenta and cord blood samples and the concentrations were strongly correlated
(r=0.89-0.98) between all compartments. Maternal blood (MB) had significantly lower p,p ́-DDE
concentrations (ng/g lw) than cord blood (CB) and breast milk (BM). The median CB/MB ratio
was 1.3 and median MB/BM ratio was 0.8. p,p ́-DDE concentrations in breast milk and cord blood
did not show significant difference and median CB/BM ratio was 1. In addition, the relative p,p`-
DDE transfer from maternal blood to breast milk and to cord blood increased when p,p`-DDE
concentrations in maternal blood increased. This study shows that Tanzanian infants are exposed
to a wide range of POPs during fetal life, which raise concerns for potential health effects. In
addition, this study found that maternal blood concentrations may lead to underestimation of
prenatal exposure, while breast milk collected close to delivery may be a more suitable indicator
of prenatal exposure
Soluble bases and cec variation across Undisturbed and disturbed coastal forests in Tanzania
No full textUnderstanding of different levels of soil calcium (Ca), magnesium (Mg), potassium (K), sodium (Na),
cation exchange capacity (CEC), and percentage base saturation (BS), is important in the
management of forest ecosystems. However, there is limited documentation on the status of these
elements in the undisturbed forest sites (CFS) crop-agriculture (ADS) and livestock grazing (DGS)
disturbances in the tropical coastal forests. This chapter attempts to address this deficit by presenting
soil fertility based on exchangeable bases’ status and variations across undisturbed forest sites (used
as a control), crop-agriculture and livestock disturbed sites in the coastal zone of Tanzania. The
chapter aims to add knowledge on the management of tropical coastal forests. Indeed, this chapter
shows that crop-agriculture and livestock grazing disturb soil chemical properties in tropical coastal
forests. Therefore, it is essential to protect undisturbed forest while putting more efforts to restore the
disturbed sites for sustainable forest management along the coastal areas
The role of savings and internal lending communities in Women’s economic empowerment: a case of Morogoro Municipality, Tanzania
No full textWomen economic empowerment is increasingly viewed as one of key elements in poverty
reduction strategies. Position of women’s economic status in Tanzania has been low
compared to men in which about 60 percent of women in Tanzania have low economic
status. This study examined the contributions of Savings and Internal Lending
Communities (SILCs) towards improving women’s economic status. Specifically, the
study examined the main source of income among women, and examined challenges
facing women in SILC. The study also assessed the level of women economic
empowerment and examined the effect of SILC on women’s economic empowerment.
A total of 100 respondents were involved. Primary data were collected using
questionnaire which was administered to 100 respondents. Key informant interview Focus
Group Discussions were also conducted so as to triangulate information gathered from
survey. Descriptive statistics was used to analyze socio-demographic characteristics, the
main income generating activities performed by women and challenges facing women in
SILC. A Cumulative Empowerment Index (CWEEI) was computed to determine the
overall level of women’s economic empowerment. An ordinal logistic regression model
was used to analyze the contribution of SILC on women’s economic empowerment.
The findings show that majority of women in SILC are involved in petty trading as their
income generating activities. It was also found that half of women in the study area have
attained medium level of empowerment. In addition, duration in SILC, involvement in
IGAs and education were good predictors to women’s economic empowerment
(P<0.005). The findings revealed further that, failure to repay the loan on time and lack of
entrepreneurial/business management skills are the major constraints facing women.
Therefore, it is recommended that stakeholders and NGOs should encourage women to
join SILC.Famil
Uncertainity reduction in climate and hydrological models predictions at catchment scale in the upper great Ruaha river sub-basin, Tanzania
No full textA Thesis 2019Water resources have become scarce in most tropical areas of Tanzania due to climate
change. Any changes to the hydrological cycle may have significant effects on the water
resources in the river basins of Tanzania. The impact of climate change on water resources
in Tanzania have been studied using General Circulation Models (GCM) which run at low
spatial resolutions of 100-300 km. The resolution is too coarse to provide useful
information about climate change impact in small catchments as many physical processes
which control local climate e.g.; vegetation, hydrology, topography is not fully
parameterized and hence results on uncertainty in model prediction.
The main aim of this research was to quantify the uncertainty in model predictions for the
Mbarali River Sub-catchment of the Upper Great Ruaha River Sub-basin in the Rufiji
River Basin, Tanzania. Three research objectives were analyzed; the first objective was to
evaluate the performance of the Coordinated Regional Downscaling Experiment Regional
Climate Model (CORDEX, Regional Climate Models) in simulating rainfall
characteristics of the Mbarali River Sub catchment. The area weighted average method
was used to calculate the average rainfall from the CORDEX RCMs and from
ERA-Interim reanalysis over the entire Mbarali River sub-catchment. Comparison
between rainfall data from CORDEX RCMs and ERA-Interim reanalysis was done to test
the ability of the CORDEX RCMs to reproduce the annual cycles, interannual variability,
annual total and trends of rainfall as presented by the ERA-Interim reanalysis.
The second objective assessed the impact of climate change on hydrological
characteristics using the Soil and Water Assessment Tool (SWAT) model. The ability of
the SWAT model to simulate catchment processes was assessed through a calibration and validation process, which was a key factor in reducing uncertainty and increasing user
confidence in its predictive abilities. The SWAT model was driven by high resolution
climate simulations for historical climate condition (1971-2000) as well as future climate
projections (2011-2040, 2041-2070 and 2071-2100) for two Representative concentration
Pathways (RCPs): RCP 4.5 and RCP 8.5. Furthermore, Ensemble of RCMs was applied
into SWAT to simulate water resources availability and the results were compared with
individual models (HIRHAM5, CCLM4, RACMO22T, RCA4). The Rainfall and
Temperature data were obtained from the selected four CORDEX RCMs driven by three
different General Circulation Models (GCMs). Inverse Distance Weight Average (IDWA)
was used to interpolate model gridded climate simulation to the location of weather
station. The third objective assessed the impacts of land use and land cover change on the
hydrology using integration of remote sensing data, QGIS and SWAT model. The land
use and land cover (LULC) maps for three window period snapshots, 1990, 2006 and
2017 were created from Landsat TM and OLI_TIRS. Supervised classification was used
to generate LULC maps using the Maximum Likelihood Algorithm and Kappa statistics
for assessment of accuracy.
The findings of the first objective are that CORDEX RCMs were able to capture well the
seasonal and annual cycles of rainfall. However, they underestimated the amount of
rainfall in March, April and May (MAM) and overestimated in October, November and
December (OND) respectively. CORDEX RCMs reproduce interannual variation of
rainfall. The source of uncertainties was revealed when the same RCMs driven by
different GCMs and when different RCMs driven by the same GCM in simulating
rainfall. It was found that the error and biases from RCMs and driving GCMs contribute
roughly equally. Overall, the evaluation found reasonable (although variable) model
capability in representing the mean climate, interannual variability and rainfall trends. The results suggest that CORDEX RCM is suitable in simulating rainfall, maximum
temperature and minimum temperature.
The findings of the second objective showed that SWAT model simulated stream flow
and water balance components differently when two different RCMs were forced by the
same GCMs as well as when the same RCMs were forced by different GCMs. The
differences are related to the formulation of the RCMs themselves. For example,
RACMO22T and HIRHAM5 driven with the same GCM (ICHEC-EARTH) simulate
different amount of stream flows, surface runoff, water yield and groundwater yield in
historical (1971–2000) as well as in present century (2011-2040), mid-century (2041-
2070) and end century (2071-2100). Ensemble RCMs projected decrease in stream flows
by 13.67% under RCP 8.5. However annual rainfall was shown to increase in averages by
1.62% under RCP 4.5 and by 1.96% for RCP 8.5 relative to the 1177.1mm of the baseline
period (1971-2000).
The results also showed that, temperature will slightly increase relative to the baseline
during present century (2011-2040) for RCP 4.5 and RCP 8.5. The ensemble average
project that the minimum temperature will increase by 14% (1.9 0 C) under RCP 8.5 and
maximum temperature by 7.68% (1.8 o C) under RCP 4.5
The findings of the third objective showed that there were significant changes in land use
and cover for the three-time periods (1990, 2006 and 2017). The cultivated land and built
up area increased from 25.69% in 1990 to 31.53% in 2006 and 43.57% in 2017 compared
to other land classes. Increase of cultivated land and built up area led to decrease in forest
cover. Forests occupied 7.54% in 1990, but decreased to 5.51% in 2006 and 5.23% in
2017. This decrease in forest cover has resulted in increased surface runoff for the same periods (2006-2017). The increase in surface runoff in the study area could be attributed
to deforestation and poor land husbandry, where during land preparation much of the
vegetation is cleared, hence decreasing canopy interception and allowing water to drain
off. Also, poor farming practices including cultivation on hillslopes without soil
conservation, reducing soil compaction, hence allowing more water to drain as surface
runoff.
The calibrated SWAT model using the three different land use and land cover change of
1990, 2006 and 2017 indicate that during the wet season, the mean monthly flow
increased by 1.48% relative to the 28.09 m 3 /s of the baseline 1990 while during the dry
season, the mean monthly flow decreased by 16.7% relative to the 0.20 m 3 /s baseline
flow. Assessment of the impacts of land use and land cover changes on catchment water
balance component revealed that surface runoff increased by 3.9% in 2006 and 9.01% in
2017 while groundwater contribution to stream flow decreased by 6.3% and 12.86% in
2006 and 2017, respectively. The decrease in stream flow could also be attributed to
abstraction of water for irrigation activities upstream of the Igawa gauge station.
The findings of the study may help basin water officers, planners in water sector and
agriculture sector in addressing uncertainty in policy and decision-making specifically
when preparing strategies and adaptations plans for river catchment. The science used in
this study can be applicable to another river basin in Tanzanian in a climate change
impact study
Economic analysis of alternative sources of energy for tobacco curing in Tabora urban district, Tabora region.
No full textA Dissertation 2019The growth of tobacco production in Tanzania has become a threat to the woodlands due
to the amount of firewood used for curing the crop. The overall objective of the research
was to assess the economic feasibility of substituting firewood with sawdust and/or rice
husks in curing tobacco. The specific objectives were to: (1) determine calorific values of
sawdust briquettes, rice husk briquettes and firewood, (2) examine quality of tobacco
cured by sawdust briquettes, rice husk briquettes and firewood, (3) compare curing costs
for the three biomass. A Bomb Calorimeter was used to determine the calorific values of
all energy sources. The grade indices were determined by dividing the value of tobacco in
each harvest/reaping per hectare to the weight of dry tobacco per hectare. The grade
indices produced by each biomass was compared by using t-test to see if they were
statistically different. The curing costs were compared by using t-test to see if they were
statistically different. The results indicated that there was no significant difference at
p>0.05 between the quality of tobacco cured by sawdust briquettes and that which was
cured by firewood. There was significant difference in curing costs at p<0.05. The study
therefore concludes that the heat content within the sawdust briquette was able to remove
the amount of water in green tobacco leaf, the quality of tobacco cured by sawdust
briquettes was the same as the quality of tobacco cured by firewood and the difference in
curing cost was brought about by the differences in amount of biomass required to cure
tobacco, the differences in distance where these biomass were collected and the
differences in labour days required in curing tobacco. The study recommended the
adoption of the use of sawdust briquettes in curing tobacco in order to reduce
deforestation rate
Management strategies to reduce postharvest losses of tomato (Solanum lycopersicum L.) in Morogoro, Tanzania
No full textLack of simple storage facilities in tomato supply chain contributes to high postharvest
losses of tomato in Tanzania. In the field, harvested tomatoes are left in an open area
and occasionally covered with grasses or sometimes under shade trees. Refrigerated
storage structures are relatively expensive to build and operate; and most people living
in rural areas cannot afford. This study was conducted to determine the effect of on
farm storage technology (zero energy cool chamber) with different harvesting stages
and the transportation effect on tomato postharvest losses. Comparisons were made on
deterioration of physiological weight and marketability of the fruits over time between
storage in zero energy cool chamber (ZECC) and ambient conditions. Tomato
harvested at mature green stage and stored under ZECC conditions exhibited
significantly (p = 0.00) longer shelf life. Only 5% of fruits physiological weight loss
was recorded in 12 days. Under ambient conditions, shelf life of tomato fruits was
between 5-8 days depending on harvesting maturity stage. The loss in marketability and
physiological weight exhibited similar trend. Use of wooden crates during
transportation of tomato from farm to a marketplace contributed much on on-transit
losses of tomato. The losses may be attributed to constant friction between tomato
surface and hardened crates. The effect of lining materials in reducing these losses was
assessed. The lining materials under observation included brown paper, hessian cloth
and sponged paper. Wooden crates lined with hessian cloth had the lowest loss
(10.6%). A significant (p < 0.0001) number of damaged tomato fruits were found in
crates with no lining. Cost benefit analysis showed that for transport of 36 wooden
crates carrying 1.44 tons of tomato, the net profit when crates are lined with hessian
cloth was 118 000 TZS compared to crates with no lining materials which was a loss of
12 000 TZS
Farmers practice versus recommended pesticides spray programmes in tomato and African eggplant production: a case of Mvomero district, Morogoro, Tanzania
No full textA Dissertation 2019The main objective of this study was to analyze the gap between the recommended
pesticides spray programmes and the actual farmers’ practices in the production of tomato
and African eggplant among farmers in Mvomero District, Morogoro Region, Tanzania.
The specific objectives were to: (i) Identify the pesticide use recommendations for tomato
and African eggplant production (ii) assess the level of farmers awareness on
recommended pesticide spray programmes (iii) compare the recommended and actual
farmers pesticide spray practice and (iv) find out the factors for farmers abidance by the
recommended practices. Cross sectional research design was applied. Data were collected
using a questionnaire for farmers and a checklist of questions for the key informants. The
region, district and villages were selected purposively while the respondents, 120 in total,
were randomly selected among the tomato and African eggplant producers. Data collected
were analyzed using statistical package for social sciences (SPSS) for quantitative data
and content analysis for qualitative data. Findings from this study show that the
recommended pesticides spray programmes comprise of; timing of application, pesticides
spray frequency, equipment used and application rates. For a farmer to make sound
decision on the application of these programmes they have to do scouting regularly in their
farms. Although all farmers had a certain level of awareness on the recommended spray
programmes; it was only 45.5% of the respondents who abode by them. The factors which
influenced farmer’s abidance by the recommendations included level of education, access
to agricultural extension services and income. For farmers to abide by the recommended
pesticides spray programmes and at the same time decrease misuse of pesticides;
extension services have to be improved especially those which promote farmer to farmer
learning
Patio-temporal diversity and abundance of fish and its contribution to household income in the little Ruaha river catchments Iringa Tanzania
No full textA Dissertation 2019Fish is an important component of aquatic biodiversity in Tanzania and plays an
important role in the national economy. However, the spatial-temporal distribution of fish
in the Little Ruaha River Catchments and its contribution to household income have not
been given sufficient evaluation. This study determined the spatiotemporal diversity and
abundance of fish, generated the information spatial distribution of fish across the
catchments and determine the contribution of fish to household income. Fish samples
were collected during dry and rain season using gillnets of 76.2 mm mesh size in three
sampling sites (in the upper reach, middle reach, and lower reach). Structured household
questionnaire and field observation were used to collect information on the contribution
of fisheries to household income. The Shannon diversity index was used to compute the
diversity of fish in the different habitats and seasons. Kruskal-Wallis and Mann Whitney
tests were used to determine the difference in fish diversity and abundance between
habitats and seasons. The contribution of fisheries to household income was assessed as
the mean proportion of household income obtained from fishing activities. A total of 250
fish individuals belonging to five species were captured. The fish species diversity and
relative abundance was higher in the lower reach compared to the upper reach.
The relative abundance of fish was statistically different (p<0.05) between habitat and
seasons. However, there was no significant (p>0.05) difference in fish diversity between
habitats and seasons. Oreochromis and Clarias were the common species across all
habitats. Fisheries contributes to an individual monthly income of up to 500 000 TSA
(US$ 220) and supplies about 51% of protein to community households. Sustainable
fisheries management in river basins contributes significantly to community livelihoods.
Management of river basins should integrate fisheries activities as among the options for
integrated river basin management