Contamination of groundnut (Arachis hypogaea L.) with Aspergillus section Flavi communities and aflatoxin at the post-harvest stage

Abstract

Groundnut (Arachis hypogaea L.) is essential to prepare numerous popular dishes across sub-Saharan Africa. However, groundnuts may contain hazardous aflatoxin levels. There is scant information on aflatoxin levels in Uganda and the causal agents of contamination in stored groundnut. High aflatoxin content hinders trading of groundnut and groundnut products in international markets, affecting Uganda's economy. The current study assessed contamination of groundnut with Aspergillus section Flavi fungi and aflatoxin under storage conditions. One hundred seventy-nine samples were sourced from farmers' household stores from 18 major groundnut-producing districts in seven agro-ecological zones (AEZ). Aflatoxin levels ranged from 0 to 1327 ng/g. Around 45% of the samples had aflatoxin levels above the Uganda National Bureau of Standards (10 ng/g). In addition, 1829 Aspergillus section Flavi isolates were recovered, and the A. flavus L morphotype dominated the communities (80%). Cropping systems, storage and climatic conditions in different AEZ influenced communities' structure composition and aflatoxin levels. There were significant (P < 0.05) differences in aflatoxin content and frequencies of Aspergillus species among AEZ and districts. The extremely high aflatoxin levels detected in samples from some districts beckoned the urgent need for management strategies are. Aflatoxin biocontrol products containing atoxigenic isolates of A. flavus, such as those detected in the study, could be used to reduce aflatoxin contamination in both field and storage conditions.