Distribution and aflatoxin productivity of Aspergillus flavus in field soils in Kanagawa Prefecture

Abstract

The distribution and aflatoxin productivity of Aspergillus flavus in field soils in Kanagawa Prefecture were investigated. A, flavus was isolated from 13 samples (8.1%) out of 160 total soil samples collected in 13 municipalities. The population of A. flavus detected in the soil samples ranged from 10 to 1, 300 CFU/g of soil. Out of 19 isolates of A, flavus, 3 strains from 3 soil samples collected in Hadano, Tsukui and Fujisawa produced aflatoxins on rice. Four strains out of 19 additional strains re-isolated from a soil sample collected in Yokohama, in which the highest population (1, 300 CFU/g) of A. flavus was found, produced a detectable amount of aflatoxins B₁ and B₂ on coconut agar, peanut agar, peanuts and trilaurin-added rice, while did not produce on rice, yeast extract-sucrose broth and sucrose-low salts broth.