the potential of aflatoxin production in the aspergillus section flavi isolates of pistachio in iran

Introduction: aflatoxin analysis shows that aspergillus section flavi strains include mixtures of the strains that are highly toxic to humans with high levels of aflatoxins, while some others produce moderate levels of aflatoxins along with nontoxigenic strains. the present study aimed to evaluate the potential of aflatoxin production in the aspergillus section flavi isolates of pistachio in iran. methods: to determine the aflatoxin-producing abilities of aspergillus section flavi isolates in pistachio orchards, 180 pistachio nut samples were collected, and fungal isolation was performed by aspergillus flavus and parasiticus agar (afpa) medium. in addition, distinct colony morphology in the coconut agar medium, yeast extract sucrose medium supplemented with methyl-β-cyclodextrin, and sucrose low salt medium were used for the distinguishing and screening of toxigenic and atoxigenic isolates. the toxigenicity and aflatoxins production level of the isolates were assayed via thin layer chromatography. results: in total, 120 isolates of various parts of the pistachio-growing areas of aspergillus section flavi were identified by the afpa, 89.15% of which were able to produce one or several types of aflatoxins, while 10.83% of the isolates had no toxin production. among the investigated isolates, 14.16% produced aflatoxins such as b1, b2, g1, and g2, while 10.83% of the isolates produced b1, b2, and g1, 34.16% of the isolates produced b1 and b2, and only 30% were able to produce the b1 aflatoxin. however, the aflatoxin production of the toxigenic isolates differed within the ranges of 39-21,548, 37-8,432, 97-2,111, and 31-810 ng/g for aflatoxins b1, b2, g1, and g2, respectively. conclusion: according to the results, 13 out of 120 investigated isolates produced no aflatoxins, and the toxigenicity of the other isolates potentially varied from extremely low to high levels.