Post-harvest interventions decrease aflatoxin and fumonisin contamination in maize and subsequent dietary exposure in Tanzanian infants : a cluster randomised-controlled trial

A cluster randomised controlled trial was performed in three agro-ecological zones of Tanzania to evaluate the effectiveness of locally available post-harvest mitigation strategies in preventing and reducing aflatoxin and fumonisin contamination in maize. A total of 300 children, each from one household, were randomly selected from 30 villages (intervention: n=15). The mitigation strategies focused on hand sorting (prior to storage and use), drying maize on mat/raised platforms, proper sun drying, application of storage insecticides and de-hulling before milling. Maize sample was collected from each household at harvest (baseline) and six months after harvest. Maize intake by each child, estimated using the 24 h dietary recall technique and its body weight measured using standard procedures were taken at six months after harvest. Aflatoxins and fumonisins in the maize samples were determined using HPLC. Follow-up (six month after harvest) data were available for 261 of the 300 households (intervention: n=136). Mean concentration of aflatoxins, or fumonisins was significantly (P<0.05) lower in the intervention than in the control group: intervention effects: mu g/kg (95% confidence interval (CI)) -4.9 (-7.3,-2.5), and -405, (-647,-162), respectively. The difference corresponds to 83 and 70% for aflatoxins, and fumonisins, respectively. At the end of the intervention, aflatoxin and fumonisin estimated mean intakes were lower in the intervention than in the control group by 78 and 65%, respectively. Six months after harvest, prevalence of underweight in the intervention group was 6.7% lower (P=0.014) than in the control group. Mean weight-for-age Z-score difference between the groups was 0.57 (95% CI; 0.16,-0.98; P=0.007). Post-harvest practices are effective in preventing and reducing aflatoxin and fumonisin contamination in maize and subsequent dietary exposure to infants. The interventions may be applied in these and other communities with similar environmental conditions or agricultural practices that favour production of aflatoxin and fumonisins in food crops

Composes Phenoliques, Phytates, Acide Citrique Et Le Fer Accessible In-Vitro De Niebes, Haricots Mungo Et Quatre Verietes De Haricots Ordinaires

Iron deficiency anaemia is highly prevalent in Tanzania affecting predominantly children and women of childbearing age. One of the major causes is the low iron bioavailability from vegetarian diets mainly due to the presence of various antinutritional factors that interfere with non-heme iron absorption. Cereals and legumes constitute the main ingredients of diets in the country providing proteins, carbohydrates, minerals and vitamins. Certain varieties of these grains contain large amounts of polyphenolics and phytate that are known to inhibit iron absorption. Varieties of legumes; cowpeas ( Vigna unguiculata ) and mung beans ( Vigna radiata L. ) and kidney beans ( Phaseolus vulgaris L. ) were analyzed for the polyphenolics and phytates. The total and in vitro accessible iron, and the citric acid were also quantified and their nutritional consequences discussed. Phenolic compounds varied widely in the analysed legumes ranging from 3.37 to 9.14 mg catechin equivalent/g and they associated negatively with in vitro accessible iron (r = - 0.367; p = 0.054). The catechol and resorcinol phenolics ranged from 1.58 to 3.51 and 1.41 to 5.37 mg catechin equivalent/g respectively and were relatively higher than galloyls that range from 0.10 to 1.52 mg tannic acid equivalent/g). Phytate ranged from 8.46 to 13.18 mg/g, total iron from 3.58 to 7.55 mg/100g and in vitro accessible iron from 0.45 to 1.04 mg/100g. Citric acid ranged from 70.8 to 205.2 mg/100g and was associated positively with in vitro accessible iron (r = 0.845; p = 0.006). Proper processing of legumes to reduce antinutritional factors to relatively lower levels is important in order to render the iron and other nutrients readily available for absorption.L&apos;anémie ferriprivée est fortement répandue en Tanzanie touchant principalement, les enfants et les femmes en âge de procréer. L&apos;une des principales causes est le faible bio-disponibilité en fer des régimes végétariens due principalement de divers facteurs antinuritionnelles qui empêchent l&apos;absorption de fer-non-hémique. Les céréales et les légumes constituent la source principale d&apos;alimentation dans ce pays. Ils fournissent les protéines les hydrates de carbone, les minéraux et les vitamines. Les variétés de légumes ; des niébés, ( Vigna unguiculata ) et haricots mungo ( Vigna radiata L. ) et des haricots ordinaires ( Phaseolus vulgaris L. ) ont été analysées pour voir leur contenance en polyphénoliques et phytates. L&apos;ensemble le fer accessible in-vitro et l&apos;acide citrique ont été également quantifiés et leur impact nutritionnel discuté. Les résultats de l&apos;analyse ont indiqué que les composés phénoliques ont largement varié allant de 3,37 à 9,14 mg équivalent/g de catéchine et ils se sont associés de façon négative au fer accessible in-vitro (r=-0,367; P=0,054) La contenance en catéchol et résorcinol (composés phénoliques) ont varié respectivement de 1,58 à 3,51 et de 1,41 à 5,37mg de catéchine équivalent/g respectivement et étaient des taux relativement plus élevés que celui de galloys qui a varié de 0,10 à 1,52mg d&apos;acide tannique/g. Les phytates ont varié de 8,46 à 13,18mg/g, le fer total a varié de 3,58 à 7,55 mg /100g et le fer accessible in-vitro de 0,45 à 1,04 mg / 100g. La teneur en acide citrique a varié de 70,8 à 205,2 mg / 100g et a été associé positivement avec le fer accessible in-vitro (r= 0,845g;p=0,006) Il est important qu&apos;un traitement approprié des légumes soit réalisé pour réduire les facteurs anti-nutritionnels à des niveaux relativement bas afin de faciliter l&apos;absorption du fer et d&apos;autres nutriments

Multiple mycotoxin co-occurence in maize grown in three agro-ecological zones of Tanzania

In this study, the co-occurrence of multiple mycotoxins in maize kernels collected from 300 households' stores in three agro-ecological zones in Tanzania was evaluated by using ultra high performance liquid chromatography/time-of-flight mass spectrometry (TOFMS) with a QuEChERS-based procedure as sample treatment. This method was validated for the analysis of the main eleven mycotoxins of health concern that can occur in maize: aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), ochratoxin A (OTA), deoxynivalenol (DON), fumonisin B1 (FB1), fumonisin B2 (FB2), HT-2 toxin, T-2 toxin and zearalenone (ZEN). From each zone one major maize producing district for home consumption was chosen and 20 villages for each district were randomly selected for sampling. All mycotoxins of health concern, except for T-2 toxin, were detected in the maize samples. Particularly high levels of AFB1 (50%; 3e1,081 mg kg 1 ), FB1 (73%; 16e18,184 mg kg 1 ), FB2 (48%; 178e38,217 mg kg 1 ) and DON (63%; 68 e2,196 mg kg 1 ) were observed. Some samples exceeded the maximum limits set in Tanzania for aflatoxins or in European regulations for other mycotoxins in unprocessed maize. Eighty seven percent of samples were contaminated with more than one mycotoxin, with 45% of samples co-contaminated by carcinogenic mycotoxins, aflatoxins and fumonisins. Significant differences in contamination pattern were observed among the three agro-ecological zones. The high incidence and at high levels (for some) of these mycotoxins in maize may have serious implications on the health of the consumers since maize constitute the staple food of most Tanzanian population. Effective strategies targeting more than one mycotoxin are encouraged to reduce contamination of maize with mycotoxins

Local post-harvest practices associated with aflatoxin and fumonisin contamination of maize in three agro ecological zones of Tanzania

A survey was undertaken of a total of 120 farmers, 40 from each of the three studied agro-ecological zones of Tanzania, to determine local post-harvest management practices associated with aflatoxin (AF) and fumonisin (FB) contamination of maize. Data on practices (collected using a structured questionnaire) and maize samples were obtained from each of the 120 farmers. FB and AF contamination in the samples were analysed by HPLC. A total of 45% and 85% of maize samples were positive for AF and FB respectively, with levels ranging from 0.1 to 269gkg(-1) for AF and from 49 to 18273gkg(-1) for FBs. Significant differences in contamination level were observed among the three agro-ecological zones. Farmers in the three agro-ecological zones practised similar practices in varying degrees. Drying, sorting and protecting maize against insect infestation are practices that showed significant association with AF or FB contamination of maize. Drying maize on mat/raised platform, sorting (damaged, discoloured and moulded grains) and application of synthetic insecticides during storage are practices that were associated with less contamination of maize with AF and FB. The results can be used to advise on effective post-harvest strategies for prevention of AF and FB contamination of maize in rural Tanzania

Impact of local pre-harvest management practices in maize on the occurrence of Fusarium species and associated mycotoxins in two agro-ecosystems in Tanzania

Knowledge on the presence of mycotoxins in Africa is fragmentary, although it can be assumed that both concentrations and prevalence in food commodities is high. The present study focuses on the presence of Fusarium species and their associated mycotoxins in maize from two geographically distant agro ecological systems in Tanzania. In a two-year survey, both Fusarium species and concomitant mycotoxins were surveyed in the Northern highlands (Hanang district) and the Eastern lowlands (Kilosa district). Parallel with this, a questionnaire on agricultural practices in both agro-ecosystems was included in this study. This allowed us to put the presence of the toxigenic Fusarium species and their mycotoxins within a relevant agricultural framework. Fusarium verticillioides, Fusarium graminearum and Fusarium poae were the predominant species in both locations although the population in the Eastern lowlands was slightly more complex comprising also Fusarium culmorum, Fusarium avenaceum and Fusarium sporotrichioides. The predominant presence of F. verticillioides resulted in a high prevalence of fumonisins in both regions. The importance of F. graminearum in the population was reflected by the presence of deoxynivalenol in the mycotoxin analysis. Although the agricultural practices differed significantly amongst both locations, only few significant correlations were detected between mycotoxin presence and crop rotation, storage conditions, and insect control measures

Risk of exposure to multiple mycotoxins from maize-based complementary foods in Tanzania

This study estimated exposure to multiple mycotoxins in 249 infants aged between 6 and 12 months in three agroecological zones of Tanzania. Maize-based complementary food intakes were estimated using two 24 h dietary recalls. Using @ Risk software, probabilistic exposure assessment was conducted by modeling maize intake data (kg/kg body weight/day) with previously determined multiple mycotoxin (except for ochratoxin A (OTA) and zearalenone (ZEA), present in only a few samples) contamination data (mu g/kg) in maize. Maize intakes ranged from 0.13 to 185 g/child/day (average = 59 +/- 36 g/child/ day). The estimated mean exposures were higher for aflatoxins (6-fold), fumonisins (3-fold), and deoxynivalenol (2-fold) than health-based guidance values of 0.017 ng/kg body weight/day, 2 mu g/kg body weight/day, and 1 mu g/kg body weight/day, respectively. The population at risk of exposures above the limits of health concern ranged from 12% for HT-2 toxin through 35% for deoxynivalenol to 100% for aflatoxins. The exposure varied among the agro-ecological zones. Strategies targeting multiple mycotoxins in maize are urgently needed to minimize exposures in Tanzania

The prevalence and risk factors associated with Iron, vitamin B12 and folate deficiencies in pregnant women: A cross-sectional study in Mbeya, Tanzania.

Maternal nutrition is an important forecaster of infant's and mother's health status in most developing countries. This study aimed at assessing the prevalence and associated risk factors of iron, vitamin B12, and folate deficiencies among pregnant women in Mbeya Tanzania. A cross-sectional study using a cluster randomized sampling was conducted among 420 pregnant women. A structured questionnaire was used to collect socio-demographic and dietary assessment. Body iron store was assessed using serum ferritin measured by immunoturbidimetric assays using a Roche Cobas 400+ biochemistry analyzer. Serum folate was measured by folate microbiological assay, while serum vitamin B12 was measured by immunochemiluminescence assay using a Roche Cobas e411 immunoassay analyzer. Multivariate analysis was performed using Poisson regression. The prevalence of iron, folate, and vitamin B12 deficiencies among pregnant women in Mbeya was 37.8%, 24.0%, and 9.7% respectively. Higher odds of iron deficiency were seen in pregnant women aged 20-24 years older [Adjusted OR = 1.20 (95%CI 1.03, 1.35)], not employed [Adjusted OR = 3.0(95%CI 1.03-1.77)] and, not received iron/folic acid supplementation [Adjusted OR = 1.11 (95%CI 1.003-1.23)]. Pregnant women with highest and middle socio-economic statuses had lower odds of vitamin B12 deficiency [Adjusted OR = 0.83 (95%CI 0.76-0.92)] and [Adjusted OR = 0.89 (95%CI 0.81-0.98)] respectively. Pregnant women who were not employed, not received iron and folic acid supplement during pregnancy and, not consumed edible vegetable cooking oil had significant higher odds of serum folate deficiency [Adjusted OR = 3.0 (95%CI 1.58-5.68)], [Adjusted OR = 1.53 (95%CI 1.21-1.93)] and, [Adjusted OR = 2.77 (1.03-7.44)] respectively. This study confirms that iron, folate and vitamin B12 deficiencies are still a major challenge among pregnant women in Tanzania. We recommend for public health interventions for the provision of vitamin B12 along with iron and folic acid supplementations, especially in pregnant women belong to low socio-economic status and limited knowledge of healthy diet