Occurrence of Fumonisins in Some Maize Meal Marketed to Consumers in Harare, Zimbabwe

Abstract

Mycotoxins are toxic secondary metabolites secreted by filamentous fungi which affect animals, plants and humanscausing a lot of diseases. Fumonisins are the types that mostly affect cereal grains. The prevalence of fumonisins in Harare marketed maize meal was investigated in 72 randomly selected samples. Fumonisin B1 and Fumonisin B2 were extracted from maize meal with methanol-water (3:1, v/v) using ultrasonic extraction. They were injected into an LC-MS system following centrifugation. A survey was also conducted to determine the measures taken by 5 major Harare millers to mitigate fumonisin contamination in the maize meal. Fumonisin B1 (FB1) was detected in all analysed samples at mean concentrations ranging between 61.45 and 265.79 µg/kg. Fumonisin B2 (FB2) was detected in only 56.9 % of the samples analysed, with a range between 13.72 µg/kg and 76.93 µg/kg. The highest total fumonisin mean concentration (FB1+FB2) was detected in maize meal with maize bran added to it (342.72 µg/kg), while the least total fumonisin mean concentration was detected in maize meal with wheat bran added to it (61.45 µg/kg). All the samples analysed were within the maximum tolerable limit (MTL) of 1000 µg/kg. However, the average probable daily intake (APDI) of fumonisins ranged between 0.82 and 4.57 µg/kg body weight/day. Maize meal with maize bran added and Roller meal had PDMI above the regulatory limit of 2 µg/kg body weight/day recommended by the World Health Organisation. The high frequency of fumonisins consumed daily in these two types of maize meal could be posing some health risks to consumers.