Survey of maize from south-western Nigeria for zearalenone, α- and β-zearalenols, fumonisin B1 and enniatins produced by Fusarium species

A survey for the natural occurrence of Fusarium mycotoxins in maize for human consumption in four south-western states of Nigeria using High Performance Liquid Chromatography coupled with Mass Spectroscopy (HPLC/ MS) showed that 93.4% of the samples were contaminated with zearalenone (ZON), alpha- and beta-zearalenols (alpha- and beta- ZOL), fumonisin B-1 (FB1) or enniatins ( ENNs). The fractions of contaminated samples were 73% for FB1 ( mean: 117 mu g kg(-1), range: 10-760 mu g kg(-1)); 57% for ZON ( mean: 49 mu g kg(-1), range: 115 - 779 mg kg(-1)) and 13% for alpha- ZOL ( mean: 63.6 mu g kg (-1), range: 32 - 181 mu g kg(-1)), while ENNs A1, B and B-1 were present in 3, 7 and 3% of the samples respectively. There was no beta- ZOL present above the quantification limits of 50 mu g kg(-1). Only the FB1 content was significantly different at the 95% confidence level among the four states. The Fusarium species most frequently isolated from maize seeds were F. verticillioides ( 70%), followed by F. sporotrichioides ( 42%), F. graminearum ( 30%), F. pallidoroseum ( 15%), F. compactum ( 12%), F. proliferatum ( 12%), F. equiseti ( 9%), F. acuminatum ( 8%) and F. subglutinans ( 4%). This is the first report of the occurrence of alpha- zearalenol and enniatins in Nigerian maize.