Mapping of endemic and risk free areas for mycotoxigenic fungi and detection of aflatoxin and fumonisin in major maize growing regions of Karnataka, India

Mycotoxins are the secondary metabolites produced by Aspergillus, Penicillium, and Fusarium that are toxic to humans and animals. Generally, mycotoxin includes aflatoxin, ochratoxin, citrinin, fumonisin, ergot alkaloid, patulin, trichothecene, zearalenone, and deoxynivalenol in different host species. Keeping the high toxicity of the mycotoxins on human and animal health, the study was conducted with the objective to assess the incidence of total mycotoxins in major maize growing regions of Karnataka. Hence, the present investigation was conducted, where seven districts were selected across Karnataka State, representing major maize-growing regions. In the field, Koppal district (14.29%) showed the highest mycotoxigenic fungal contamination, followed by Mandya district (12.86%). Shivamogga district (47.20%) had the highest mycotoxigenic fungal contamination in godowns and market conditions, followed by Mandya (46.40%) and Koppal districts (44.00%). Aspergillus flavus isolates were detected through ELISA, and all isolates were highly potent in producing aflatoxin (AfB1). The maximum AfB1 production was recorded by AM-10 (2919.3 µg kg^–1) whereas, minimum was reported by AM-20 (2125.1 µg kg^–1). The production of fumonisin (FB1) by Fusarium verticillioides was detected through LC-MS, which revealed that only four isolates were positive, of which FM-16 (30 µg kg^–1) and FM-15 (14.75 µg kg^–1) were highly potent in nature. This is the first description regarding the natural co-occurrence of aflatoxin and fumonisin with maize in Karnataka State (India).