Assessment of dietary exposure and levels of mycotoxins in sorghum from Niger State of Nigeria

Abstract

This study reports levels of mycotoxins in sorghum from Niger State, Nigeria, and provides a comprehensive assessment of their potential health risks by combining mycotoxin levels and dietary exposure assessment. A total of 240 samples of red and white sorghum were collected from both stores and markets across four microclimatic zones. Fungal species were identified using a dilution plate method. Aflatoxins (AFs), deoxynivalenol, nivalenol, and ochratoxin (OTA) were quantified using HPLC, whereas cyclopiazonic acid, fumonisins (FUMs) and zearalenone were quantified using ELISA. A. flavus and A. fumigatus were dominant fungal species followed by F. verticilloides, A. oryzae and P. verrucosum. Aflatoxins (mean: 29.97 µg/kg) were detected in all samples, whereas OTA (mean: 37.5 µg/kg) and FUMs (mean: 3269.8 µg/kg) were detected in 72% and 50% of the samples, respectively. Mycotoxins frequently co-occurred in binary mixtures of AFs + OTA and AFs + FUMs. Dietary exposure estimates were highest for FUMs at 230% of TDI and margin of exposures (MOEs) for both AFs and OTA (<10,000) indicating a potential risk associated with combined exposure to AFs and OTA. The Risk of hepatocellular carcinoma cases (HCC/year) attributable to AFs and OTA exposure from sorghum was estimated to be 5.99 × 10⁵ and 0.24 × 10⁵ cases for HBsAg + individuals based on 13.6% HBV incidence. Similarly, the HCC/year for AFs and OTA were assessed to be 3.59 × 10⁵ and 0.14 × 10⁵ at an 8.1% prevalence rate. Therefore, the results of this study demonstrate the high prevalence and dietary exposure to mycotoxins through sorghum consumption, raising public health and trade concerns.

Keywords:

• Aflatoxins
• cyclopiazonic acid
• deoxynivalenol
• nivalenol
• ochratoxin A
• Niger State
• sorghum

Acknowledgements

We appreciate the technical assistance from the Department of Animal Health, Northwest University, Mafikeng, South Africa. This work was partly funded by the Tertiary Education Fund (TETFUND), Nigeria (TETFUND/FUTMINNA/2019/B7/16).

Authors contributions

Fatimah Omolola Badmos: Data collection and curation, investigation, methodology, validation, writing – original draft, writing – review & editing; Hadiza Lami Muhammad, Achi Dabara, Funmilola Adefolalu, Susan Salubuyi, Abdullahi Abdulkadir, Victor Tope Oyetunji, Daniel O Apeh, Hadiza Kudu Muhammad, Mulunda Mwanza: Conceptualization, methodology, resources, supervision, validation, writing – review & editing; Maurice Monjerezi, Limbikani Matumba: Validation, visualization, writing – review & editing.

Ethical approval

All the experiments carried out in this work comply with the current laws of the federal republic of Nigeria and South Africa where the work was performed.

Disclosure statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.