Identification of Aspergillus flavus and aflatoxins contamination in inflorescences of wild grasses in Iran

Abstract

Wild grasses are the most important primary feedstuffs which are susceptible to contamination with toxigenic fungi belonging to Aspergillus spp. In order to explore diversity of Aspergillus species associated with the inflorescences of gramineous weeds, infected inflorescences were collected from wild grasses in western parts of Iran. Fifty-six Aspergillus isolates were obtained from all diseased spikes and based on morphological features identified as 4 species i.e. Aspergillus niger (26) followed by Aspergillus flavus (24), Aspergillus fumigatus (4), and Aspergillus japonicus (2). The identification of A. flavus was confirmed using species specific primers of AFLA-F/AFLA-R by producing amplicons about 413 bp. In this study, aflatoxins (AFs) contamination of wild grasses was evaluated by enzyme linked immunosorbent assay (ELISA). Natural occurrence of AFs could be detected in 24 samples ranging from 0.63134.86 μg/kg. The highest AFT levels were detected in samples from Ravansar, Bisetoon, Mahidasht, and Sarpol Zehab (up to 50 μg/kg), which is more than the recommended limits by European Union standard and National Standard of Iran (20 μg/kg for animal feed).