FUSARIUM AND MYCOTOXINS PROFILE OF MAIZE (Zea Mays) AND SORGHUM (Sorghum bicolor) GROWN IN NIGER STATE, NIGERIA

Abstract

Fusarium is a filamentous fungal found to contaminate agricultural produce and is capable of causing diseases in humans and animals. Sixty-four composite samples of different varieties of maize and sorghum were formed from 480 samples collected from both stores and market from the four micro-climatic zones of Niger State. Fusarium species isolation from the composite samples were carried out using plate dilution method and identification was done using identification keys and atlas. Deoxynivalenol (DON) and Nivalenol (NIV) were identified and quantified using High Performance Liquid Chromatography (HPLC) while fumonisin (FUM) and zearalenone (ZEN) were quantified using Enzyme Linked Immunosorbent Assay (ELISA). Occurrence data obtained were used to estimate exposure level and risk associated with the studied mycotoxins. Fusarium species isolated in maize and sorghum are Fusarium verticilloides, F. sporotrichioides, F. graminerium, F. equiseti F. subglutinans F. nygamai, F. semitectum, F. solani and F. oxysporum. Fusarium verticilloides was the leading species found in maize and sorghum with percentage frequency of 59.38 %, while F.oxysporum was the least species found with percentage frequency of 7.8. Deoxynivalenol was detected in 37.5 % and 31.25 % of maize and sorghum samples at concentration range of (0-342.62) µg/kg and (0-40.84 ) µg/kg, whereas NIV concentration was found in range of (0-28.80) µg/kg and (0-12.85) µg/kg, for maize and sorghum, with incidence rate of 28.13 % and 25.00 % respectively. Approximately 91% and 56 % of maize and sorghum samples were contaminated with FUM in concentration range of 0-4889.3 µg/kg and 0-3269.81 µg/kg respectively. ZEN contamination of maize and sorghum is in the range of (0-235.79) µg/kg and (0-277.37) µg/kg. Fifty percent of the analysed samples were co-contaminated with deoxynivalenol, nivalenol, fumonisin and zearalenone. Based on the dietary intake calculated for average consumers of maize and sorghum across the zones, exposure to FUM was found to be the highest (9125.83 µg/kg bw/day and 4604.77 µg/kg bw/day), accounting for 456.29 % (maize) and 230.24 % (sorghum) of the tolerable daily intake (TDI). The demonstrated high prevalence to this harmful and carcinogenic compound raises public health and trade concerns.