Detection of aflatoxin production by fungi in spice samples using HPLC and direct visual cultural methods

Abstract

Spice samples detected to be positive for aflatoxin using HPLC were analyzed for their total fungal population and the presence of aflatoxicogenic fungi using direct visual cultural methods. Screening was done using colony fluorescence upon exposure to UV, ammonia vapour test and characteristics in Aspergillus differentiation media. The aflatoxicogenic fungi isolated were morphologically identified to be Aspergillus flavus with the lone exception of a strain that showed similarity with Aspergillus parasiticus. Although, no direct correlation between the numbers of potential aflatoxin producing fungi with the levels of aflatoxin detected in the spice samples could be observed, it is interesting to note that spice samples with low fungal counts were detected to be having more quantity of aflatoxins using HPLC analysis. This leads us to conclude that aflatoxin production by aflatoxicogenic fungi may be considerably reduced or below etectable levels in spice samples having a high population of competing non-producing fungi.