Mycotoxin contamination of sorghum and its contribution to human dietary exposure in four sub-Saharan countries

ABSTRACT

This research aimed at evaluating the safety, and the type, level and prevalence of mycotoxins in grain sorghum of four sub-Saharan African (SSA) countries (Burkina Faso, Ethiopia, Mali and Sudan). A multi-analyte LC-MS/MS method for quantification of 23 mycotoxins (nivalenol, deoxynivalenol, fusarenon X, neosolaniol, 3-acetyl deoxynivalenol, 15-acetyl deoxynivalenol, diacetoxyscirpenol, roquefortine C, HT-2 toxin, alternariol, T-2 toxin, FB1, FB2, FB3, zearalenone, aflatoxin G₁, aflatoxin G₂, aflatoxin B₁, aflatoxin B₂, sterigmatocystin, OTA, altenuene, alternariol monomethylether) was applied to different sorghum matrices. Of the 1533 analysed samples, 33% were contaminated with at least one of the following mycotoxins: aflatoxins, fumonisins, sterigmatocystin, Alternaria toxins, OTA and zearalenone. Country of origin, colour, source and collection period of sorghum samples significantly influenced the type, level and prevalence of mycotoxins. Sterigmatocystin (15%), fumonisins (17%) and aflatoxins (13%) were the most prevalent. FB1 (274 ± 585 µg/kg) had the highest mean concentration followed by FB2 (214 ± 308 µg/kg) while diacetoxyscirpenol (8.12 ± 19.2 µg/kg) and HT-2 (11.9 ± 0.00 µg/kg) had the lowest concentrations. Neosolaniol, fusarenon-X, 3-acetyl deoxynivalenol, 15-acetyl deoxynivalenol, T-2 toxin, nivalenol and roquefortine C were not detected in any of the samples. Sudan had the lowest prevalence and mean concentration of all mycotoxins. Pink sorghum had the highest concentrations of fumonisins and aflatoxins. Mycotoxins from Aspergillus spp. and Alternaria spp. are the mycotoxins of concern in SSA grain sorghum with regard to prevalence, concentration and possible health risk from exposure. Based on the performed risk characterisation, daily consumption of sorghum containing aflatoxins, alternariol, alternariol monomethyl ether, sterigmatocystin and OTA could result in exceeding the established health-based guidance values for these toxins.

KEYWORDS:

• Prevalence
• health effects
• sub-Saharan Africa
• mycotoxins
• sorghum

Acknowledgements

This project to carry out surveys on mycotoxins in sorghum in four countries in the African region was made possible through a contribution from the EU to the FAO/WHO Codex Trust Fund. The results of the project were used for this paper. In addition to named authors, technical guidance and oversight to the projects were provided by WHO regional food safety officers Dr Mohamed Elmi, Dr Soren Madsen and Ms Lusubilo Mwamakamba. Dr Kerstin Hell was responsible for overall coordination of the four projects. The national experts supporting the in country surveys were Dr Karim Koudougou (Burkina Faso); Dr Emana Getu Degaga, Professor Negussie Retta (Ethiopia); Mme Maïga Farmata Yaro, Monsieur Bamory Diarra (Mali) and Dr Dina Ahmed Hassan Ibrahim, Mr Adam Ali Mohamed (Sudan). Technical contributions to the research from Christ’l Detavernier and Tom Devos of the Laboratory of Food Analysis at Ghent University are highly appreciated.

Disclosure statement

No potential conflict of interest was reported by the authors.

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Funding

This work was supported by the FAO/WHO Codex Trust Fund.