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

Microbial and heavy metal contamination of pineapple products processed by small and medium scale processing enterprises in Rwanda

Fruit products are increasingly consumed but highly prone to microbial deterioration if not adequately processed and stored. The present study was conducted to evaluate the microbial and heavy metal concentrations of packed pineapple nectars, syrups and jams processed by 10 Small and Medium scale pineapple processing Enterprises (SMEs) over a storage duration of 12 months. Collected samples were analysed to determine whether the levels of microbial and heavy metal concentrations were in line with maximum permissible limits set by Codex Alimentarius Commission (CAC), East African Standards (EAS) and Rwanda Bureau of Standards (RBS). The samples were tested for yeasts and moulds, total plate counts, Faecal coliforms, total coliforms, Escherichia coli, Salmonella, Shigella and Staphylococcus aureus using tested International Organization for Standardization (ISO) microbial determination methods. Quantitative determination of heavy metals: zinc, iron, lead, copper, cadmium and aluminium was carried out by Atomic Absorption Spectrophotometer (AAS). Pineapple products were free from most of the microorganisms but only nectars from 30% of SMEs were highly contaminated above the permissible Codex and RBS limits with total plate counts &gt;300 CFU/ml  and yeasts and mould counts &gt;300 CFU/ml. The mean levels of zinc, iron, copper and aluminium were within the acceptable recommended Codex and RBS standard values but the levels of lead and cadmium were above those permissible standard values. These results indicated that some fruit processors in Rwanda may not be observing good manufacturing and hygienic practices, leading to a need for improved post-harvest and processing guidelines, better monitoring and enforcement, and additional research into heavy-metal ingress in the manufacturing process.Keywords: Pineapple,  juices,  jams, microbial contamination,  heavy metal, Rwanda.African Journal of Biotechnology, Vol 13(39) 3977-398

Popping Quality and Acceptability of Sorghum Pops in Selected Sorghum (Sorghum bicolour (L) Moench) Genotypes

Forty sorghum genotypes comprising five local and 35 introductions were evaluated for physical, popping qualities and grain yield. Twenty five of the forty genotypes were further characterized for sensory and acceptability qualities. The study revealed genotypic differences in grain yield, grain physical characteristics and popping qualities. Grain yield ranged from 751 to 2861 kg ha-1, with only 10 percent of the genotypes had grain yield of more than 2000 kg ha-1. Popping yield ranged from 61 to 95 percent and 25 percent of the genotypes yielding above 90 percent. More than 50 percent of the genotypes had popped volume of 12 to 14.3 mililitres (ml). Sorghum pops prepared from the genotype 80c 2241, MR114-90M11 and SDSH 49 were the most preferred for color, while TX2767 was most preferred for both texture and taste. These genotypes were accepted with a high hedonic rating of between like very much to like extremely. These genotypes were among the top eight in popping yield rating. The most liked sorghum pops were those that were prepared from the white colored sorghum genotypes, while the red and particularly the brown colored ones were least liked for both color and taste. Generally the sorghum introductions were superior in popping and acceptability qualities than the local cultivars. Based on these results it is recommended that farmers should be encouraged to grow the top ranking genotypes for preparation of their traditional foods as well as for popping purposes. UNISWA Research Journal of Agriculture, Science and Technology Vol 3 (1) 1999: pp 44-4

Human exposure to fumonisins from home grown maize in Tanzania

Fumonisins contaminate maize worldwide resulting in unacceptable fumonisin exposures in people relying on maize as staple food. This study determined fumonisins B1 (FB1) and B2 (FB2) in maize from 120 rural households: 30 from each of four main maize producing regions of Tabora, Ruvuma, Iringa and Kilimanjaro in Tanzania in order to estimate total fumonisin (FB1 + FB2) exposures to adult individuals in the households. The average daily per capita maize consumption of 771 g, recommended by the Tanzania Food and Nutrition Centre (TFNC) for an adult relying on it as a main meal, and also average daily per capita maize consumptions of 129, 308 and 356 g documented for Tanzania, were used in the exposure estimation. The fumonisins were determined by HPLC using fluorescence detection. Total fumonisins exposure (µg/kg body weight (bw)/day) was determined by multiplying average daily per capita maize consumption (kg) by fumonisin level in maize (µg/kg) from a given household and then dividing by an average bw of an adult of 60 kg. Of the 120 samples, 52% were contaminated with fumonisins at levels of up to 11,048 µg/kg (median; 363 µg/kg). Based on the recommended maize consumption of 771 g/person/day, fumonisin exposures to adult individuals in 38% of the households would exceed the provisional maximum tolerable daily intake (PMTDI) of 2 µg/kg bw, recommended by the Joint FAO/WHO Expert Committee on Food Additives. At the least documented maize consumption of 129 g/person/day, fumonisin exposures in 16% of the households were still above the PMTDI. Reduction of the maize consumption level to 40 g/person/day is an impractical, and reduction of the maximum contamination level to 155 µg/kg is a possibly practical, option for effective minimisation of fumonisin exposures in these communities. A relatively larger study is needed in order to generate comprehensive data for the formulation of appropriate strategies to minimise fumonisin exposures in Tanzania

Human exposure to fumonisins from home grown maize in Tanzania

Fumonisins contaminate maize worldwide resulting in unacceptable fumonisin exposures in people relying on maize as staple food. This study determined fumonisins B1 (FB1) and B2 (FB2) in maize from 120 rural households: 30 from each of four main maize producing regions of Tabora, Ruvuma, Iringa and Kilimanjaro in Tanzania in order to estimate total fumonisin (FB1 + FB2) exposures to adult individuals in the households. The average daily per capita maize consumption of 771 g, recommended by the Tanzania Food and Nutrition Centre (TFNC) for an adult relying on it as a main meal, and also average daily per capita maize consumptions of 129, 308 and 356 g documented for Tanzania, were used in the exposure estimation. The fumonisins were determined by HPLC using fluorescence detection. Total fumonisins exposure (µg/kg body weight (bw)/day) was determined by multiplying average daily per capita maize consumption (kg) by fumonisin level in maize (µg/kg) from a given household and then dividing by an average bw of an adult of 60 kg. Of the 120 samples, 52% were contaminated with fumonisins at levels of up to 11,048 µg/kg (median; 363 µg/kg). Based on the recommended maize consumption of 771 g/person/day, fumonisin exposures to adult individuals in 38% of the households would exceed the provisional maximum tolerable daily intake (PMTDI) of 2 µg/kg bw, recommended by the Joint FAO/WHO Expert Committee on Food Additives. At the least documented maize consumption of 129 g/person/day, fumonisin exposures in 16% of the households were still above the PMTDI. Reduction of the maize consumption level to 40 g/person/day is an impractical, and reduction of the maximum contamination level to 155 µg/kg is a possibly practical, option for effective minimisation of fumonisin exposures in these communities. A relatively larger study is needed in order to generate comprehensive data for the formulation of appropriate strategies to minimise fumonisin exposures in Tanzania

Fumonisins exposure from freshly harvested and stored maize and its relationship with traditional agronomic practices in Rombo District, Tanzania

The exposure to fumonisins from the maize harvest of 2006 (before and after sorting and storage) for 67 families was assessed along with its statistical association with agronomic practices in Rombo, Tanzania. Fumonisins were determined by high-performance liquid chromatography (HPLC) and exposure estimated based on 60 kg body weight and maize intake of 356 g per person day-1. Based on contamination in the unsorted maize, exposure for 27% of the families would exceed the provisional maximum tolerable daily intake of 2 µg kg-1 body weight. The odds ratio of fumonisin exposure from maize hybrid 614 (H614) were: two times higher compared with non-H614 maize (p = 0.089); and five times higher when the maize was grown without fertilizer (p = 0.004). Sorting maize before storage reduced the percentage of families with unacceptable exposures to 6%. Therefore, the results imply that planting of the non-H614 seeds using fertilizers combined with pre-storage sorting of maize significantly minimizes fumonisins exposure in Rombo. A field experiment to verify these findings is needed

Co-occurrence of fumonisins with aflatoxins in home-stored maize for human consumption in rural villages of Tanzania

This study determined maize-user practices that influence the presence of fumonisin and aflatoxin contamination of maize in food consumed in the rural areas of Tanzania. Samples of the 2005 maize harvest in Tanzania were collected from 120 households and examined for fumonisins and aflatoxins. Information on whether the maize was sorted to remove defective (visibly damaged or mouldy) maize before storage and whether the damaged and mouldy maize or the non-dehulled maize was used as food was also collected. In addition, the percentage of defective kernels in the samples was determined. Ninety per cent of the households sorted out defective maize, 45% consumed the defective maize and 30% consumed non-dehulled maize. In 52% of the samples fumonisins were determined at levels up to 11,048 g kg-1 (median = 363 g kg-1) and in 15% exceeded 1000 g kg-1; the maximum tolerable limit (MTL) for fumonisins in maize for human consumption in other countries. Aflatoxins were detected in 18% of the samples at levels up to 158 g kg-1 (median = 24 g kg-1). Twelve per cent of the samples exceeded the Tanzanian limit for total aflatoxins (10 g kg-1). Aflatoxins co-occurred with fumonisins in 10% of the samples. The percentage defective kernels (mean = 22%) correlated positively (r = 0.39) with the fumonisin levels. Tanzanians are at a risk of exposure to fumonisins and aflatoxins in maize. There is a need for further research on fumonisin and aflatoxin exposure in Tanzania to develop appropriate control strategies

Co-occurrence of fumonisins with aflatoxins in home-stored maize for human consumption in rural villages of Tanzania

This study determined maize-user practices that influence the presence of fumonisin and aflatoxin contamination of maize in food consumed in the rural areas of Tanzania. Samples of the 2005 maize harvest in Tanzania were collected from 120 households and examined for fumonisins and aflatoxins. Information on whether the maize was sorted to remove defective (visibly damaged or mouldy) maize before storage and whether the damaged and mouldy maize or the non-dehulled maize was used as food was also collected. In addition, the percentage of defective kernels in the samples was determined. Ninety per cent of the households sorted out defective maize, 45% consumed the defective maize and 30% consumed non-dehulled maize. In 52% of the samples fumonisins were determined at levels up to 11,048 µg kg-1 (median = 363 µg kg-1) and in 15% exceeded 1000 µg kg-1; the maximum tolerable limit (MTL) for fumonisins in maize for human consumption in other countries. Aflatoxins were detected in 18% of the samples at levels up to 158 µg kg-1 (median = 24 µg kg-1). Twelve per cent of the samples exceeded the Tanzanian limit for total aflatoxins (10 µg kg-1). Aflatoxins co-occurred with fumonisins in 10% of the samples. The percentage defective kernels (mean = 22%) correlated positively (r = 0.39) with the fumonisin levels. Tanzanians are at a risk of exposure to fumonisins and aflatoxins in maize. There is a need for further research on fumonisin and aflatoxin exposure in Tanzania to develop appropriate control strategies