Distribution of indigenous strains of atoxigenic and toxigenic Aspergillus flavus and Aspergillus parasiticus in maize and peanuts agro-ecological zones of Kenya

Abstract

Background Grains of important food and export crops in Africa are susceptible to contamination by toxin-producing moulds. Aflatoxins are mycotoxins associated with liver damage and cancer in humans and animals. These toxic substances are produced by fungi (such as Aspergillus flavus and Aspergillus parasiticus) in food and feed exposed to poor conditions during crop cultivation, storage or processing of harvest. The presence of aflatoxins in especially maize and peanuts in Kenya is of great concern. Recent developments in the application of atoxigenic strains of these fungi as biological control agents against toxigenic strains could be a solution to the problem. The objective of this study was to isolate, identify and characterize atoxigenic and toxigenic strains of A. flavus and A. parasiticus in Kenya, and investigate possible application of atoxigenic strains in control of aflatoxin levels in maize and peanuts. Fungal communities in soils of maize and peanut fields were examined to determine the distributions of aflatoxin-producing Aspergillus species and to identify endemic atoxigenic strains. 220 isolates belonging to A. flavus and A. parasiticus were collected randomly from soils of maize and peanuts fields in seven agro-ecological zones and characterized using morphological and physiological examination.