Browsing by Author "Haesaert, Geert"

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    Characterization of Ugandan Endemic Aspergillus Species and Identification of Non-Aflatoxigenic Isolates for Potential Biocontrol of Aflatoxins
    (Toxins, 2022) Wokorach, Godfrey; Landschoot, Sofie; Lakot, Amerida; Arihona Karyeija, Sidney; Audenaert, Kris; Echodu, Richard; Haesaert, Geert
    Acute stunting in children, liver cancer, and death often occur due to human exposure to aflatoxins in food. The severity of aflatoxin contamination depends on the type of Aspergillus fungus infecting the crops. In this study, Aspergillus species were isolated from households’ staple foods and were characterized for different aflatoxin chemotypes. The non-aflatoxigenic chemotypes were evaluated for their ability to reduce aflatoxin levels produced by aflatoxigenic A. flavus strains on maize grains. Aspergillus flavus (63%), A. tamarii (14%), and A. niger (23%) were the main species present. The A. flavus species included isolates that predominantly produced aflatoxins B1 and B2, with most isolates producing a high amount (>20 ug/ L) of aflatoxin B1 (AFB1), and a marginal proportion of them also producing G aflatoxins with a higher level of aflatoxin G1 (AFG1) than AFB1. Some non-aflatoxigenic A. tamarii demonstrated a strong ability to reduce the level of AFB1 by more than 95% when co-inoculated with aflatoxigenic A. flavus. Therefore, field evaluation of both non-aflatoxigenic A. flavus and A. tamarii would be an important step toward developing biocontrol agents for mitigating field contamination of crops with aflatoxins in Uganda.
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    Genetic Characterization of Fungal Biodiversity in Storage Grains: Towards Enhancing Food Safety in Northern Uganda
    (Microorganisms, 2021) Wokorach, Godfrey; Landschoot, Sofie; Audenaert, Kris; Echodu, Richard; Haesaert, Geert
    Worldwide fungal contamination leads to both quantitative and qualitative grain losses during crop growth and/or storage. A greater proportion of grains contamination with toxins often occurs in sub-Saharan Africa, where control measures are limited. We determined fungal diversity and their toxin production ability in household grains meant for human consumption to highlight the risk of mycotoxin exposure among people from northern Uganda. The study underlines the high diversity of fungi that group into 15 genera; many of which are plant pathogens with toxigenic potential. Fusarium verticillioides was the most common fungal species isolated from household grains. The study also indicates that northern Uganda is favored by a high proportion of toxigenic isolates of F. verticillioides, F. andiyazi, and F. proliferatum, which are characterized by a high fumonisins production capability. The fumonisins production ability was not dependent on the species, grain types, and haplotype group to which the isolates belong. The contamination of most household grains with fungi capable of producing a high amount of toxin shows that most people are exposed to an elevated amount of mycotoxins, which shows the frequent problems with mycotoxins that have been reported in most parts of sub-Saharan Africa.
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    Is nodding syndrome in northern Uganda linked to consumption of mycotoxin contaminated food grains?
    (BMC Research Notes, 2018) Echodu, Richard; Edema, Hilary; Malinga, Geoffrey Maxwell; Hendy, Adam; Colebunders, Robert; Kaducu, Joyce Moriku; Ovuga, Emilio; Haesaert, Geert
    Nodding syndrome (NS) is a type of epilepsy characterized by repeated head-nodding seizures that appear in previously healthy children between 3 and 18 years of age. In 2012, during a WHO International Meeting on NS in Kampala, Uganda, it was recommended that fungal contamination of foods should be investigated as a possible cause of the disease. We therefore aimed to assess whether consumption of fungal mycotoxins contributes to NS development. Results: We detected similar high levels of total aflatoxin and ochratoxin in mostly millet, sorghum, maize and groundnuts in both households with and without children with NS. Furthermore, there was no significant association between concentrations of total aflatoxin, ochratoxin and doxynivalenol and the presence of children with NS in households. In conclusion, our results show no supporting evidence for the association of NS with consumption of mycotoxins in contaminated foods.
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    Mycotoxin profile of staple grains in northern Uganda: Understanding the level of human exposure and potential risks
    (Food Control, 2021) Wokorach, Godfrey; Landschoot, Sofie; Anena, Juliet; Audenaert, Kris; Echodu, Richard; Haesaert, Geert
    Mycotoxins are toxic metabolites of fungi that contaminate food and feed. These toxins can cause acute and chronic health threats to both humans and animals. In sub-Saharan Africa, exposure to mycotoxins is chronic and under-reported. The study explores contamination of grains (sorghum, maize, groundnut, millet) with four mycotoxins (aflatoxins, fumonisins, ochratoxins, and deoxynivalenol) and dietary exposure to quantify associated health risks in northern Uganda. The results underscored the high prevalence of mycotoxins, only 7% of the samples were free from toxins. Sorghum grains seemed to be the most susceptible to toxin contamination, whereas in millet the toxin levels were, in general, the lowest. Besides, the results showed that the majority of grains were contaminated with more than one mycotoxin and that the toxin pattern was dependent on the grain type. Co-contamination with all four mycotoxins mainly occurred in sorghum grains. Besides the differences between grain types, there were also significant differences in toxins levels depending on the district where the grains came from. The estimated daily intakes for the mycotoxins were far above the recommended tolerable daily intake (TDI), especially for sorghum. So, it can be concluded that the majority of the people whose diet is mainly based on sorghum are exposed to multiple mycotoxins in a single diet and at a dose above the TDI. Such exposure to multiple mycotoxins elevates the associated health risks. Millet grains, which were the least contaminated, can provide an alternative to sorghum. However, to tackle the mycotoxin problem, other control and prevention mechanisms, e.g. good agricultural practices and optimized storage must be further explored and implemented in sub-Saharan Africa.
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    Prevalence of aflatoxin, ochratoxin and deoxynivalenol in cereal grains in northern Uganda: Implication for food safety and health
    (Toxicology reports, 2019) Echodu, Richard; Malinga, Geoffrey Maxwell; Moriku Kaducu, Joyce; Ovuga, Emilio; Haesaert, Geert
    Mycotoxin contamination of cereals is a significant health risk for humans and animals, particularly in developing countries. To gain insight into food safety related to agricultural practices, we assessed levels of mycotoxin contamination in 105 samples of food grains raised and stored for consumption by rural households in the postconflict districts of Kitgum and Lamwo in Northern Uganda. Aflatoxin, ochratoxin and deoxynivalenol (DON) contamination was assessed by quantitative enzyme-linked immunosorbent assay. Total aflatoxin in the foods analyzed varied from nd (not detected) to 68.2 μg/Kg. Ochratoxin ranged from 0.1 to 16.4 μg/Kg. DON ranged from nd to 2606 μg/Kg. The mean concentration of total aflatoxins was significantly higher (P=0.002) in sorghum than in millet, maize and sesame seeds. Frequency of co-occurrence of two mycotoxins ranged from 8.3 to 100%, with the highest being aflatoxin and ochratoxin in sorghum. Co-occurrence of all three mycotoxins ranged from 8.3 to 35.3%, with the highest again being in sorghum. Mean levels of aflatoxins concentration in sorghum samples were 11.8 μg/Kg, exceeding the Ugandan national regulatory limits of 10 μg/Kg. Furthermore, 46.5% of the sorghum consumed in both districts exceeded this limit, and 86.1% of sorghum samples exceeded the European Union (E.U.) maximum tolerable limit of 4 μg/Kg. The Estimated Daily Intake (EDI) and Hazard Indices (HI) values were in the range of 1.2×10−5–91.521 and 1.3×10−7 to 0.0059, respectively. In conclusion, our results provide evidence of high levels of mycotoxin contamination and co-occurrence in food grains in Northern Uganda with aflatoxins and ochratoxins at high levels in all the cereal types analyzed. Consumption of cereals cultivated in this region poses no health risk of mycotoxins exposure since HI values obtained were less than 1.