Real-time PCR and agar plating method to predict fusarium verticillioides and fumonisin B1 content in Nigerian maize

Abstract

Eighty maize grain samples collected in Nigeria were investigated for fumonisin B1 (FB1) content and Fusarium verticillioides colonization. F. verticillioides DNA was quantified by species-specific real-time PCR and living propagules of the fungus were counted by agar-plating method. FB1 was detected in 55 (68.7%) of the total samples (mean: 98.5 μg/kg, range: 10 to 714 μg/kg) at 10 μg/kg detection limit. The mean amount of F. verticillioides DNA determined by real-time PCR was 49.7 μg/kg (range: 10-126.7 μg/kg), while agar plate method showed the presence of F. verticillioides in 45 samples (mean incidence: 21.0%, range: 6.7-60.0%). There was correlation ties between F. verticillioides DNA by real time PCR and fungal colonization by agar plate method (R = 0.71, p = 00001 at 95% confidence level), and means of FB1 and F. verticillioides DNA in the yellow and white maize were significantly different. Despite the high consumption of maize in Nigeria, the amount of FB1 ingested by consumers appears to be low. The estimated daily intake of fumonisins was 0.21 μg/kg body weight per day.