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J. M. Misihairabgwi
Department of Biochemistry and Microbiology, School of Medicine, University of Namibia, Windhoek 10005, Namibia.

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Journal article
Published: 16 March 2019 in Toxins
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Sorghum malts, which are important ingredients in traditional fermented beverages, are commonly infected by mycotoxigenic fungi and mycotoxins may transfer into the beverages, risking consumers' health. Liquid chromatography⁻tandem mass spectrometry was used to determine variation of fungal metabolites in 81 sorghum malts processed for brewing of Namibian beverages, otombo (n = 45) and omalodu (n = 36). Co-occurrence of European Union (EU)-regulated mycotoxins, such as patulin, aflatoxins (B₁, B₂, and G₂), and fumonisins (B₁, B₂, and B₃) was detected in both malts with a prevalence range of 2⁻84%. Aflatoxin B₁ was quantified in omalodu (44%) and otombo malts (14%), with 20% of omalodu malts and 40% of otombo malts having levels above the EU allowable limit. Fumonisin B₁ was quantified in both omalodu (84%) and otombo (42%) malts. Emerging mycotoxins, aflatoxin precursors, and ergot alkaloids were quantified in both malts. Notably, 102 metabolites were quantified in both malts, with 96% in omalodu malts and 93% in otombo malts. An average of 48 metabolites were quantified in otombo malts while an average of 67 metabolites were quantified in omalodu malts. The study accentuates the need to monitor mycotoxins in sorghum malts intended for brewing and to determine their fate in the beverages.

ACS Style

Sylvia N. Nafuka; Jane M. Misihairabgwi; Ronnie Bock; Anthony Ishola; Michael Sulyok; Rudolf Krska. Variation of Fungal Metabolites in Sorghum Malts Used to Prepare Namibian Traditional Fermented Beverages Omalodu and Otombo. Toxins 2019, 11, 165 .

AMA Style

Sylvia N. Nafuka, Jane M. Misihairabgwi, Ronnie Bock, Anthony Ishola, Michael Sulyok, Rudolf Krska. Variation of Fungal Metabolites in Sorghum Malts Used to Prepare Namibian Traditional Fermented Beverages Omalodu and Otombo. Toxins. 2019; 11 (3):165.

Chicago/Turabian Style

Sylvia N. Nafuka; Jane M. Misihairabgwi; Ronnie Bock; Anthony Ishola; Michael Sulyok; Rudolf Krska. 2019. "Variation of Fungal Metabolites in Sorghum Malts Used to Prepare Namibian Traditional Fermented Beverages Omalodu and Otombo." Toxins 11, no. 3: 165.

Journal article
Published: 18 September 2018 in World Mycotoxin Journal
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Sorghum and pearl millet, ingredients for the popular Namibian traditional fermented beverage oshikundu, are prone to fungal infection, raising concerns for consumer health from mycotoxin exposure. This study aimed at determining the diversity of fungal metabolites in street-vended ingredients and their transfer rates into oshikundu. A total of 105 samples (40 sorghum malt, 40 pearl millet, 25 oshikundu) were analysed for 700 fungal, bacterial and plant metabolites, using liquid chromatography-tandem mass spectrometry. Of 98 quantified metabolites, 84 were fungal, some being mycotoxins. Aspergillus metabolites were most prevalent (50%, n=42), including aflatoxins, aflatoxin precursors, cyclopiazonic acid and 3-nitropropionic acid from Aspergillus flavus; helvolic acid, gliotoxin and fumiquinazolines from Aspergillus fumigatus and cytochalasin E, patulin and tryptoquivalines from Aspergillus clavatus. High levels of up to 2,280 μg/kg for cyclopiazonic acid and 11,900 μg/kg for 3-nitropropionic acid were quantified in sorghum malts. Other metabolites included fumonisins, curvularin, alternariol and dihydroergosine produced by Fusarium, Penicillium, Alternaria and Claviceps genera, respectively. European Union legislated mycotoxins occurred in cereals at a prevalence range of 3-75%, while none were quantifiable in oshikundu. Aflatoxin B1 was quantified in pearl millet meals (13%) and sorghum malts (50%), with 15% sorghum malts having levels above the European Union regulatory limit of 5 μg/kg. Fumonisin B1 was quantified in pearl millet meals (50%) and sorghum malts (75%) at maximum levels of 3,060 μg/kg and 123 μg/kg respectively, and levels in 5% pearl millet meals were above the European Union regulatory limit of 2,000 μg/kg. Zearalenone and ochratoxin A were quantified in the cereals at levels below European Union regulatory limits. For most metabolites quantifiable in oshikundu, transfer rates from cereals to oshikundu were above 50%, necessitating the use of good quality ingredients for preparing oshikundu and assessment of consumer exposure to mycotoxins.

ACS Style

J.M. Misihairabgwi; A. Ishola; I. Quaye; M. Sulyok; R. Krska. Diversity and fate of fungal metabolites during the preparation of oshikundu, a Namibian traditional fermented beverage. World Mycotoxin Journal 2018, 11, 471 -481.

AMA Style

J.M. Misihairabgwi, A. Ishola, I. Quaye, M. Sulyok, R. Krska. Diversity and fate of fungal metabolites during the preparation of oshikundu, a Namibian traditional fermented beverage. World Mycotoxin Journal. 2018; 11 (3):471-481.

Chicago/Turabian Style

J.M. Misihairabgwi; A. Ishola; I. Quaye; M. Sulyok; R. Krska. 2018. "Diversity and fate of fungal metabolites during the preparation of oshikundu, a Namibian traditional fermented beverage." World Mycotoxin Journal 11, no. 3: 471-481.

Reviews
Published: 25 September 2017 in Critical Reviews in Food Science and Nutrition
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Major staple foods in Southern Africa are prone to mycotoxin contamination, posing health risks to consumers and consequent economic losses. Regional climatic zones favor the growth of one or more main mycotoxin producing fungi, Aspergillus, Fusarium and Penicillium. Aflatoxin contamination is mainly reported in maize, peanuts and their products, fumonisin contamination in maize and maize products and patulin in apple juice. Lack of awareness of occurrence and risks of mycotoxins, poor agricultural practices and undiversified diets predispose populations to dietary mycotoxin exposure. Due to a scarcity of reports in Southern Africa, reviews on mycotoxin contamination of foods in Africa have mainly focused on Central, Eastern and Western Africa. However, over the last decade, a substantial number of reports of dietary mycotoxins in South Africa have been documented, with fewer reports documented in Botswana, Lesotho, Malawi, Mozambique, Zambia and Zimbabwe. Despite the reported high dietary levels of mycotoxins, legislation for their control is absent in most countries in the region. This review presents an up-to-date documentation of the epidemiology of mycotoxins in agricultural food commodities and discusses the implications on public health, current and recommended mitigation strategies, legislation, and challenges of mycotoxin research in Southern Africa.

ACS Style

J. M. Misihairabgwi; C. N. Ezekiel; Michael Sulyok; G. S. Shephard; R. Krska. Mycotoxin contamination of foods in Southern Africa: A 10-year review (2007–2016). Critical Reviews in Food Science and Nutrition 2017, 59, 43 -58.

AMA Style

J. M. Misihairabgwi, C. N. Ezekiel, Michael Sulyok, G. S. Shephard, R. Krska. Mycotoxin contamination of foods in Southern Africa: A 10-year review (2007–2016). Critical Reviews in Food Science and Nutrition. 2017; 59 (1):43-58.

Chicago/Turabian Style

J. M. Misihairabgwi; C. N. Ezekiel; Michael Sulyok; G. S. Shephard; R. Krska. 2017. "Mycotoxin contamination of foods in Southern Africa: A 10-year review (2007–2016)." Critical Reviews in Food Science and Nutrition 59, no. 1: 43-58.