Comparison of Aflatoxin Yield from Peanut Isolate of Aspergillus flavus with Other Isolates

Background: Mouldy growth in food commodities by aflatoxin producing fungi is a serious health concern to animals as well as human beings due to the harmful effects of aflatoxins like hepatotoxicity, carcinogenicity, impairment of protein synthesis, formation of DNA adducts, etc. even in minute concentrations. A tropical climate with moderate temperature, high humidity and heavy rainfall provides optimal conditions for the growth of aflatoxin producing fungi like Aspergillus flavus in different food items. The current study was to examine if the substrate(s) in a food item has any role to play in aflatoxin production by A. flavus. Methods: The fungus was isolated from ten different edible materials and identified using standard procedure. The isolates were cultured in potato dextrose agar slants keeping the culture conditions identical in triplicates. The toxin extracted using chloroform as solvent and downstream processing to get crude toxin was quantified on the basis of dry weight. Thin layer chromatography was done and the fluorescence of the toxins from different isolates was visualised under high wavelength of ultra-violet light with standard Aflatoxin B1 chromatographed vis-a-vis to confirm presence of the toxin in all the extracted toxins. Result: Results of the extracted toxin dry weight comparison between different isolates as well as the fluorescence intensity in the chromatograms revealed that contaminated peanut isolate of A. flavus yielded the highest amount of crude toxin. Thus, the results indicate that there are some factor(s) in peanut that promote(s) aflatoxin production by A. flavus. This information was further used for formulating potato dextrose agar media for isolation of aflatoxin producing fungi by incorporating peanut extract in the media and comparing the amount of crude toxin yield.