Discovery of the Relationship between Distribution and Aflatoxin Production Capacity of Aspergillus species and Soil Types in Peanut Planting Areas

In order to study the relationship between the distribution and aflatoxin production capacity of Aspergillus species and soil types, 35 soil samples were collected from the main peanut planting areas in Xiangyang, which has 19.7 thousand square kilometers and is located in a special area with different soil types. The soil types of peanut planting areas in Xiangyang are mainly sandy loam and clay loam, and most of the soil is acidic, providing unique nature conditions for this study. The results showed that the Aspergillus sp. population in clay loam (9050 cfu/g) was significantly larger than that in sandy loam (3080 cfu/g). The percentage of atoxigenic Aspergillus strains isolated from sandy loam samples was higher than that from clay loam samples, reaching 58.5%. Meanwhile the proportion of high toxin-producing strains from clay loam (39.7%) was much higher than that from sandy loam (7.3%). Under suitable culture conditions, the average aflatoxin production capacity of Aspergillus isolates from clay loam samples (236.97 μg/L) was higher than that of strains from sandy loam samples (80.01 μg/L). The results inferred that under the same regional climate conditions, the density and aflatoxin production capacity of Aspergillus sp. in clay loam soil were significantly higher than that in sandy loam soil. Therefore, peanuts from these planting areas are at a relatively higher risk of contamination by Aspergillus sp. and aflatoxins.