Phycocyanin as a proxy for algal blooms in surface waters: case study of Ukerewe Island, Tanzania

Knowledge of the parameters that contribute to water body eutrophication is essential for proper monitoring and management of water quality for human consumption. This study assessed water quality parameters in relation to phycocyanin (PC) as a proxy indicator for harmful algal blooms (HABs). Samples were collected from 23 water sources – lakes, wells, springs and boreholes – in selected villages, for six months. Parameters measured included temperature, pH, redox potential, dissolved oxygen, electrical conductivity, total dissolved solids, nitrate nitrogen, nitrite nitrogen, phosphorus, reactive phosphate and total chlorophyll, which were related to (PC) occurrence. The PC concentration detected in Lake Victoria ranged from 5 to 58.4 μg/l above the WHO alert level and exceeded that in other water sources by almost 30 μg/l (P < 0.001). Univariate relationship between water quality parameters and PC indicates association with temperature, redox potential, total chlorophyll, nitrate nitrogen, nitrite nitrogen, phosphate and reactive phosphorus (P < 0.001). The multivariate model indicates that redox potential, nitrate nitrogen and phosphorus are significant statistically (P < 0.05). A predictive model indicates that nitrate nitrogen and reactive phosphorus contribute significantly to PC occurrence whereby unit (1 mg/l) increases in these parameters increase PC by 9.55 and 4.38 μg/l (P < 0.05) respectively. This study demonstrates that water quality parameters can be used to predict increases in PC and hence as a proxy for HABs. It remains important to be able to classify algal blooms, to understand which species are present and their potential cyanotoxin production

Post-production Losses in Iodine Concentration of Salt Hamper the Control of Iodine Deficiency Disorders: A Case Study in Northern Ethiopia

Iodine is essential for good function of the thyroid, and its deficiency is of public-health importance in Ethiopia. Iodization of salt is an effective and sustainable strategy to prevent and control iodine deficiency in large populations. The effectiveness of salt-iodization programmes depends on the conservation of iodine concentration in salt at various stages of the supply-chain. The overall objective of the study was to assess the loss of iodine in salt from production to consumption and to estimate the proportion of adults, especially pregnant women, at risk of dietary iodine insufficiency. A cross-sectional study was conducted during February-April 2007 in northern Ethiopia. Iodine concentrations of salt samples from producers (n=41), retailers (n=7), and consumers (n=32) were determined using iodiometric titration. A risk assessment was conducted for dietary iodine insufficiency among adults, including pregnant women, using a semi-probabilistic approach. The concentration of iodine in the sampled salts decreased by 57% from the production site to the consumers. The assessment of exposure showed that adults in 63% (n=20) of the households, including 90% (n=29) with pregnant women, were at risk of insufficient iodine intake. A monitoring and evaluation system needs to be established to ensure adequate supply of iodine along the distribution chain. Special attention is needed for the retailers and consumers. At these levels, dissemination of information regarding proper storage and handling of iodized salt is necessary to address the reported loss of iodine from salt

Country and Economic Assessment for Aflatoxin Contamination and Control in Tanzania; A supplement to the 2012 Report

This report supplements the report released by the Abt Associates Inc in 2013 on the Country and Economic Assessment for Aflatoxins in Tanzania. It is an output of the work done by the United Republic of Tanzania, through national consultants led by the Nelson Mandela African Institution of Science and Technology (NM-AIST), with support from the African Union Commission through the Partnership for Aflatoxin Control in Africa (PACA). Extensive information on knowledge and awareness of aflatoxins among Tanzanians as well as information on aflatoxin contamination for maize and groundnuts was collected. Data of aflatoxins contamination in rice from three main rice growing districts of Tanzania; Kilosa (Morogoro), Mbarali (Mbeya) and Misungwi (Shinyanga) were also collected. A review of existing food safety policies and those being developed, to identify gaps that could be addressed to strengthen the food safety system of Tanzania was also performed. In addition, a health and economic impact analysis for aflatoxins, based on aflatoxin biomarker data for children in Tabora, Iringa and Kilimanjaro, was done. The Tanzania Food Security Investment Plan (TAFSIP) document was reviewed to identify areas into which aflatoxin measures could be mainstreamed. The situation analysis and action planning was conducted in consultation with several key stakeholders including the government line ministries, regional economic communities (RECs), donors and the private sector. It was found that the general awareness about aflatoxins was low, amongst stakeholders interviewed. Furthermore, it was found that knowledge about Good Agricultural Practices (GAP) is not widespread and that guidelines on GAP were not availablePAC

The Risk of Dietary Exposure to Pesticide Residues and Its Association with Pesticide Application Practices among Vegetable Farmers in Arusha, Tanzani

This research article published by the Canadian Center of Science and Education, 2018This study was conducted to assess dietary exposure to pesticide residues and pesticide application practices leading to the presence of these residues among vegetable farmers in Arusha, Tanzania. Face-to-face interviews using semi-structured questionnaires (including 24-hour recall and food frequency questionnaire techniques) were conducted to collect information on pesticide application practices and vegetable consumption, from 76 farmers. A sample of ready-to-eat vegetables was collected from each farmer's household to determine the level of pesticide residues. Pesticide residues were analyzed by gas chromatography-mass spectroscopy A deterministic approach was used to assess dietary exposure to pesticide residues. Among the analyzed samples, 31.4% contained detectable levels of organophosphate residues. The detected organophosphates were dimethoate (mean, 8.56 mg kg-1 ), acephate (mean, 2.9 mg kg-1 ), profenofos (mean, 8.44 mg kg-1 ), dichlorvos (mean, 20.8 mg kg-1 ) and malathion (mean, 5.47 mg kg-1 ). The mean exposure for dimethoate (0.0021 mg kg-1 body weight (wt) day-1 was higher than its corresponding acceptable daily intakes of 0.002 mg kg-1 bwd-1 resulting in hazard quotient of 1.044 with a consequent hazard index of 1.19 for organophosphates. Pyrethroid pesticides (permethrin, cypermethrin, and lambda-cyhalothrin) were also detected but at a lower frequency (17.1%) and hazard index (0.029). The exposure to pesticide residues was significantly associated with limited access to expert advice on pesticide application (p=0.031, adjusted odds ratio=6.56) and over-dosage (p=0.038, adjusted odds ratio=3.751).The risk may be minimized by increasing access to support by extension service providing guidance on good practices and ensuring application of appropriate doses for pesticides

Risk of exposures of pesticide residues from tomato in Tanzania

This research article published by Academic Journal, 2017Tomato contributes the highest percent to the fruit and vegetables consumed in Tanzania. Its high consumption is attributed to the presence of bioactive compounds and vitamins known to prevent non-communicable diseases. Pesticides used to control pests and diseases cause direct accumulation of pesticide residues in food. Consumption of pesticide contaminated tomato increases the risk of pesticide exposure. This review is on types of pesticides used in tomato production, health effects of pesticides, levels of pesticide residues in tomatoes, dietary pesticide exposure, awareness on pesticides effects and preventive measures as well as policies governing pesticide use in Tanzania. Clearly, there is evidence of extensive use of pesticides in tomato production, limited knowledge regarding pesticide use, as well as weak regulatory framework for pesticide use. Importantly, levels of pesticide residues in tomatoes consumed in Tanzania exceed the recommended maximum residual limits. In order to assure pesticide safety of food, there is a need to identify and control farmers' practices which are highly associated with pesticide contamination in tomatoes

Childhood dietary exposure of aflatoxins and fumonisins in Tanzania: A review

This research article published by Taylor & Francis Online, 2020Aflatoxins (AFs) and Fumonisins (FBs) are common contaminants of maize, from secondary metabolites of fungi. Presence of AFs and FBs in maize-based complimentary food is evident in various studies conducted in Tanzania and elsewhere. Consequently, Infant and Young children (IYC) aged between 6 and 24 months in Tanzania who consume monotonous maize-based foods are at a high risk of exposure to these toxins. The AF or FB exposures have been linked to low awareness and inadequate knowledge or limited skills of IYC feeding practices among mothers and caregivers. This review reveals that more researches are needed to identify appropriate feeding practices in Tanzania to improve child growth. Meanwhile, stakeholders should direct efforts on education to subsistence farmers including mothers and caregivers on interventions to minimize mycotoxin contamination of cereal and nut-based complementary foods in the country

Inadequate management of complementary foods contributes to the risk of aflatoxin exposure and low nutrition status among children

This research article published by World Mycotoxin Journal, 2018Early exposure to aflatoxins through complementary food is linked to impaired growth in childhood. The current study assessed the household’s practices on management of complementary foods in relation to the risk of aflatoxin exposure and poor nutritional status among infant and young children in Tanzania. A cross-sectional study of complementary feeding practices, aflatoxin exposure and nutritional status was conducted to 101 infants and young children aged between 6-23 months in Dodoma region of Tanzania. The intake of complementary food was estimated by using repeated 24 h dietary recall. Flour used as complementary food was sampled from each of the 101 families and aflatoxins were analysed using high-performance liquid chromatography. A deterministic approach was used to estimate dietary exposure of aflatoxins in the complementary foods. Anthropometric measurements were taken and rates of stunting, underweight and wasting estimated according to the WHO standard procedures. Multivariate logistic regression analysis was used to assess the association between feeding practices and aflatoxin exposure or the growth performance among subjects. The average consumption of complementary flour was 118 g per child per day and 52% of the flours contained groundnuts. AFB1 was detected in 42.5% of the flour and levels ranged from 0.3 to 2,128.0 μg/kg (mean 228.11±49.84 μg/kg). Dietary exposures of aflatoxin B1 ranged from 0.1 to 23,172.81 ng/kg body weight per day (mean 1,337±392.5 ng/kg). Of the subjects, 40.4% (95% CI; 29.8; 50.9) were stunted and significant association was found between stunted growth and dietary exposure of AFB1 (adjusted odd ratio (AOR)=5.9; 95% CI: 0.019-0.028). Early introduction of cereal-and groundnut-based complementary foods in Tanzania is associated with high risk of aflatoxin exposure and impaired growth in children. There is need to integrate aflatoxin management measures in the guidelines for Infant and Young Children Feeding of Tanzania

Control of Fusarium verticillioides (Sacc.) Nirenberg and fumonisins by using a combination of crop protection products and fertilization

Fusarium verticillioides is the most common fungal pathogen associated with maize ear rot in Tanzania. In a two-year trial, we investigated the efficacy of crop protection (insecticide and/or fungicide) and fertilizer (nitrogen and/or phosphorus) treatments in reducing the occurrence of F. verticillioides and its mycotoxins in maize grown in Tanzania. Seasonal differences were seen to have a substantial influence on the incidence and severity of insect infestation, Fusarium ear and kernel rot, biomass of F. verticillioides and contamination with fumonisins. With regard to the application of fertilizers, it was concluded that the impact on maize stalk borer injury, Fusarium symptoms and fumonisin levels was not significant, whereas crop protection significantly reduced maize damage. The application of an insecticide was most effective in reducing insect injury and as a result of the reduced insect injury the insecticide treatment also resulted in a significant decrease in Fusarium symptoms. In 2014, fumonisin levels were also significantly lower in maize treated with an insecticide. Additionally, significant positive correlations between insect damage and Fusarium symptoms were observed. In conclusion, this study clearly shows that application of an insecticide alone or in combination with a fungicide at anthesis significantly reduces insect damage and consequently reduces F. verticillioides infection and associated fumonisin contamination

Socioeconomic Characteristics Influencing Level of Awareness of Aflatoxin Contamination of Feeds among Livestock Farmers in Meru District of Tanzania

This research article published by Hindawi, 2018Aflatoxins occurrence in feeds challenges human and animal health. Farmers’ awareness status of these toxins has an effect on their level of exposure. The study assessed the influence of socioeconomic characteristics of farmers on their awareness of aflatoxin contamination of feeds. Data were collected from 258 households and analysed by SPSS program for descriptive statistics and association between socioeconomic characteristics and awareness of aflatoxin contamination of feeds. Over seventy percent of the farmers had never heard about aflatoxins. Education level, specialization, and period of keeping animals had significant influence on aflatoxin awareness. Hearing about aflatoxins was six times higher among farmers who studied life or social sciences than those without specialization and those who studied other fields. Awareness that aflatoxins may occur in feeds was twice higher among farmers with higher education than those with lower education. Perception that aflatoxins in feeds are detoxifiable was threefold higher among young people (with ≤10-year period of keeping animals) than among older ones. Awareness of aflatoxins was particularly low among farmers with low education and those without exposure to life or social sciences and vice versa. Sensitization is recommended to raise farmers’ awareness on aflatoxin contamination of feeds and incorporating aflatoxin knowledge in school curricula