Occurrence and molecular detection of toxigenic Aspergillus species in food grain samples from India

The aim of this study was to detect the presence of different mycotoxigenic Aspergillus species in major food grains from southern states of India, namely maize, paddy, groundnut and sorghum. A total of 200 isolates recovered from 320 grain samples from four southern states were tested for their toxin chemotypes using high-performance liquid chromatography (HPLC), high-performance thin layer chromatography (HPTLC) and polymerase chain reaction (PCR) methods. The diversity and distribution of the isolates were recorded in terms of their frequency, density, importance value index and diversity indices.

Among the different grain samples tested, 83% of groundnut, 69% of maize, 57% of sorghum and 29% of paddy samples had aflatoxin B1 (AFB1) levels above the allowed limit, while 82% of maize, 70% of sorghum, 42% of paddy and 17% of groundnut samples had ochratoxin A (OTA) concentrations higher than the permitted threshold (5 µg kg⁻¹).

Since the southern states of India are temperate regions, environmental factors, especially temperature and relative humidity, may be responsible for the high levels of mycotoxins present in the grains studied. Therefore there is a need to generate awareness among farmers and consumers about the possible adverse health effects of high levels of mycotoxins present in different food grains.