Fate of aflatoxin in cereals and cereal products during processing

Author: Flora Oluwafemi

Received 22 June 2004, accepted 15 August 2004.

Abstract

The fate of aflatoxin during processing of contaminated maize grains into “guguru” (roasted maize/popcorn) at different temperature regimes and at different time intervals showed that aflatoxin can be destroyed with heat. Gradual reductions in aflatoxin B1 levels were observed as processing temperature and time increased. Processing temperatures of 100, 150, 200 and 250°C with 30 minutes time intervals for a maximum period of 2 hours were used. Reduction of aflatoxin (99.5%) was achieved with grains processed at 250°C for 30 minutes. The other levels of reductions were from 20% at 100°C for 30 minutes to maximum of 97.6% reduction at 200°C for 120 minutes. The concentration of aflatoxin in the raw materials used for brewing showed that all materials such as sorghum, corn grit and barley had low levels of aflatoxin. The cumulative effects of aflatoxin in the raw materials caused an increase in the aflatoxin level to about 5.20 µg/kg. Boiling the wort at 100°C gave a reduction of 10.4%. Further reduction of aflatoxin to 0.450 µg/kg was achieved during lagering. The pH before and after lagering was 5.2 and 3.7 respectively.