Aspergillus flavus population isolated from soil of Argentina's peanut‐growing region. Sclerotia production and toxigenic profile

The Aspergillus flavus population was evaluated in the period 1998–2001 in soil samples from the peanut‐growing region in Argentina. A total of 369 A flavus isolates were examined for sclerotia, aflatoxin and cyclopiazonic acid production. The L phenotype was isolated in a higher percentage than the S phenotype and represented 59% of the total isolates. Statistical analysis showed significant differences between L, S and non‐sclerotial strains with regard to aflatoxin and cyclopiazonic acid production (p < 0.05). The S strains produced higher mycotoxin levels than the L and non‐sclerotial strains. About 10% of the S strains had an unusual pattern of mycotoxin production because they simultaneously produce aflatoxins B and G and CPA. The SBG strains isolated in the present study have all morphological and microscopic characteristics of A flavus. These strains are of concern in food safety, as there is a higher probability of aflatoxin contamination in peanuts.