Occurrence of toxigenic fungi and aflatoxin potential of aspergillus spp. Strains associated with subsistence farmed crops in Haiti

Abstract

Subsistence farming and poor storage facilities favor toxigenic fungal contamination and mycotoxin accumulation in staple foods from tropical countries such as Haiti. The present preliminary study was designed to evaluate the occurrence of toxigenic fungi in Haitian foodstuffs to define the mycotoxin risk associated with Haitian crops. The objectives of this research were to determine the distribution of toxigenic fungi in the Haitian crops maize, moringa, and peanut seeds and to screen Aspergillus section Flavi (ASF) isolates for production of aflatoxins B1 and G1 in vitro. Maize, moringa, and peanut samples were contaminated by potential toxigenic fungal taxa, mainly ASF and Fusarium spp. The isolation frequency of Aspergillus spp. and Fusarium spp. was influenced by locality and thus by farming systems, storage systems, and weather conditions. Particularly for ASF in peanut and maize samples, isolation frequencies were directly related to the growing season length. The present study represents the first report of contamination by toxigenic fungi and aflatoxin in moringa seeds, posing concerns about the safety of these seeds, which people in Haiti commonly consume. Most (80%) of the Haitian ASF strains were capable of producing aflatoxins, indicating that Haitian conditions clearly favor the colonization of toxigenic ASF strains over atoxigenic strains. ASF strains producing both aflatoxins B1 and G1 were found. Understanding the distribution of toxigenic ASF in Haitian crops and foodstuffs is important for determining accurate toxicological risks because the toxic profile of ASF is species specific. The occurrence of toxigenic fungi and the profiles of the ASF found in various crops highlight the need to prevent formation of aflatoxins in Haitian crops. This study provides relevant preliminary baseline data for guiding the development of legislation regulating the quality and safety of crops in this low-income country.