Abstract

Study on the fungi and some mycotoxins (Aflatoxin B₁ - AFB₁, ochratoxin A - OTA and zearalenone - ZEN) contaminating rice (Oryza sativa) in Niger State of Nigeria was carried out. One thousand and sixty two fungi were isolated and identified from one hundred and ninety six mouldy rice samples collected from the state. The major fungal genera contaminating rice were Aspergillus, Penicillium, Fusarium, Alternaria, Mucor, Rhizopus, Trichoderma, Curvularia, Helminthosporium and Cladosporium. The most prevalent fungal species on rice were .Penicillium spp., A. flavus, A. parasiticus, A. niger, Mucor spp., Rhizopus spp. and Alternaria spp. The commonest fungal contaminants of the dry, harmattan; dry-hot and rainy seasons were A. niger, Penicillium spp. and A. flavus respectively. AFB₁ was detected in 97 of the samples analyzed at concentrations between 20-1642 ug/kg. Fifty six of the one hundred and forty samples analyzed for OTA contained the toxin (24 – 1164 ug/kg). Zearalenone was found in ninety three of the one hundred and ninety six mouldy rice samples analyzed at concentrations of between 24 and 1169 ug/kg. Twenty two samples were concurrently contaminated with the three toxins while seven others were found to contain both AFB₁ and OTA. AFB₁ and ZEN occurred together in twelve samples, and eight samples contained both OTA and ZEN.

Key words: Fungi, mycotoxins, rice, aflatoxin B₁ ochratoxin A, zearalenone.