Distribution of Aspergillus flavus and aflatoxin accumulation in stored maize grains across three agro-ecologies in Ghana

摘要

Aflatoxins are carcinogenic secondary metabolites produced mainly by two species of Aspergillus fungi, (A. flavus and A. parasiticus). The toxin contaminates maize grains during the developmental stage as well as in storage. Grains with contamination levels above 20 ng/g are usually destroyed in the USA while the European Union and Japan allow 2-4 ng/g and nil respectively. Ghana lacks regulatory infrastructure for monitoring fungal contamination and detection of aflatoxin in grains prior to market. Therefore, this study assessed the extent of A. flavus contamination together with other mould on maize and total aflatoxin accumulation among stored maize grains across 34 towns and villages under three agro-ecologies in Ghana during the minor crop season of 2015-2016. A. flavus, was identified as the most predominant contaminant and recorded average percentage contamination of 56.7%, 30.6%, 53.5% and 45.6% on grains sampled across four communities (Fumesua, Wenchi, Ejura and Akomadan), respectively. Total aflatoxins recorded in the samples per community were in the range of below limit of detection (LOD) to 692 ng/g, 23 ng/g, 945 ng/g and 112 ng/g for Fumesua, Wenchi, Ejura and Akomadan, respectively. These dangerous upper limits demand urgent attention in the area of aflatoxin resistance breeding in maize to help address the aflatoxin menace in Ghana.