Abstract

Aflatoxin B₁ (AFB₁) is one of the most harmful mycotoxins to humans, animals, and crops that result in illnesses and economic losses. Maize, the most important staple food in most southern African countries, is susceptible to these fungi infections throughout its growth, harvest, transport and storage. In this study, we report on the incidence of AFB₁ (determined by indirect competitive ELISA) contamination in maize from Malawi and the effect of traditional maize-flour production procedures on the final AFB₁ levels. AFB₁ was detected in 45.3% of the maize samples with 12.3% of them exceeding 5 µg/kg (FAO median AFB₁ MTL). The traditional flour production procedures reduced AFB₁ significantly in the order: soaking of dehulled maize (72.4±5.4, 75.4±3.5 and 80.9±5.3% for 24, 48 and 72 h soaking periods, respectively) > dehulling of maize (mean 29.3±5.4%) > sun drying (11.7% max). Sun drying followed pseudo-first order kinetics in AFB₁. A maximum AFB₁ reduction of 88.1 ± 3.1% was achieved using a sequence of dehulling, soaking for 72 h and sun drying the flour for 4.5 h.

Key words: Aflatoxin B₁, maize, Malawi.