Climate Change and Severe Drought Impact on Aflatoxins and Fungi in Brazil Nuts: A Molecular Approach

Abstract

The Brazil nut production chain, which is reliant on Amazonian environmental conditions, is significantly affected by climate change, particularly extreme droughts, which decrease production and compromise sanitary quality. This study evaluated the influence of severe drought on aflatoxin concentrations and sequence toxigenic fungi in Brazil nuts harvested during the 2023 off-season. Aflatoxins were quantified using high-performance liquid chromatography, while fungal sequencing involved DNA extraction, PCR, and sequencing analysis. Findings indicated that all Brazil nut samples collected during extreme drought contained detectable aflatoxins, with 10% exceeding the legal threshold of 10 µg/kg. Phylogenetic analysis identified four isolates as Penicillium citrinum. Additional morphological and sequencing analyses identified Aspergillus species from the Circumdati and Flavi sections, although one isolate could not be taxonomically classified. These results demonstrate the aflatoxin production by fungi in Brazil nuts in an unprecedented way under drought conditions. Furthermore, the diversity of fungal species during drought underscores the risk of contamination, emphasizing the necessity for monitoring future harvests to improve management and ensure product safety.