Fungi and some mycotoxins contaminating rice (Oryza Sativa) in Niger State, Nigeria

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,  elminthosporium 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.