Mycopathologia 151: 29–33, 2000. © 2001 Kluwer Academic Publishers. Printed in the Netherlands. 29 Isolation of aflatoxigenic strains of Aspergillus and detection of aflatoxin B 1 from feeds in India ∗ T.K. Dutta & P. Das Indian Veterinary Research Institute, India Received 15 February 2000; accepted 13 April 2001 Abstract In a preliminary study, 256 feed samples collected from different parts of Northern India were examined for the presence of aflatoxigenic strains of Aspergillus flavus/parasiticus and for detection of Aflatoxin B 1 (AFB 1 ). Out of 198 A. flavus and 15 A. parasiticus strains isolated, 76% and 86% respectively, were found to be toxigenic. Aflatoxin B 1 content of these feeds, as estimated by thin layer chromatography (TLC) and enzyme linked immun- osorbent assay (ELISA) were very high (average 0.412 ± 0.154 ppm) in comparison to the permissible Indian regulation level (0.03 ppm). Seasonal variation of incidence and level of toxin in feed was recorded and it was high during monsoon/post monsoon period. Key words: aflatoxin B 1 , Aspergillus flavus/parasiticus, feed, India Introduction Mycotoxins are toxic secondary metabolites produced by fungi in cereal grains, animal feed and food. Aflatoxins (AFs) are mainly produced by A. flavus link ex Fries and A. parasiticus Spear [1–3]. The major tox- ins produced by A. flavus are AFB 1 and B 2 whereas, A. parasiticus produces another two additional toxins G 1 and G 2 . Due to extreme toxicity and wide spread occurrence in staple food and feed, AFB 1 currently is the only mycotoxin that is regulated by the FDA [4]. Aspergilli are the major contaminant of feed stuff [5]. Most of the feed and/or feed ingredients tested for the presence of aflatoxigenic fungi in India and abroad revealed the predominance of A. flavus over A. para- siticus [6–13]. The high incidence of aflatoxigenic A. flavus isolates seems to be an overall feature [14, 15]. The presence of high level of AFB 1 of food and feed stuffs has been reported by several workers in differ- ent parts of India [16–22]. In a multicentre survey groundnut and maize were analysed for the presence of AFB 1 . Approximately 21% of groundnut and 26% of maize were containing AFB 1 beyond the level of Indian standard for consumption (30 μg/kg) [23, 24]. In the present work, a preliminary study was con- ducted to evaluate the occurrence of aflatoxigenic ∗ Published in June 2001. strains of A. flavus/parasiticus and to detect the AFB 1 content in livestock and poultry feed randomly collec- ted from Northern parts of India. Materials and methods Feed samples Two hundred fifty six feed samples comprising maize, groundnut cake, fish meal, poultry ration, cattle ra- tion etc. were collected randomly from different places of Northern India. Sampling was carried out during summer (81), post monsoon (101) and winter (74) following organized sampling procedure [25]. Isolation of A. flavus and A. parasiticus from feed Mycological analysis of feed samples were per- formed on Sabouraud’s dextrose agar plates contain- ing chloramphenical. Ground samples were first sus- pended and diluted (10 fold dilution) in 0.2% agar and 0.1 ml of each dilution were spread over the surface of the medium. The plates were incubated at 28 ◦ C for 5–7 days. Identification of Aspergillus sp. were made as per Raper and Fennell [26].