Production of aflatoxin and cyclopiazonic acid by Aspergillus flavus strains isolate from peanuts / Produção de aflatoxinas e ácido ciclopiazônico por cepas de Aspergillus flavus isoladas de amendoim

Aspergillus flavus is a filamentous fungus that can produce aflatoxins and cyclopiazonic acid, and the presence of these mycotoxins in food and feed can lead to a toxic effect on humans and animals. Strains of A. flavus producing aflatoxin and cyclopiazonic acid are often isolated from peanuts, indicating the the co-occcurrence of these toxins in the natural substrate. In this study, we isolated 47 strains of A. flavus on peanut kernels and hulls during different stages of fruit ripening and its storage. Of the isolated strains, we assessed the potential for aflatoxin and cyclopiazonic acid production, in which 91.5% could produce aflatoxins and 70% produced cyclopiazonic acid; 63.8% produced both toxins and 2.1% produced no toxin. The presence of toxigenic A. flavus strains in peanut samples indicate a potential risk of contamination of these products, if they are exposed to environmental conditions that are favorable to fungal growth and mycotoxin production.

Aspergillus flavus é um fungo filamentoso que pode produzir aflatoxinas e لcido ciclopiazônico, sendo que a presença dessas micotoxinas em alimentos e raçُes pode levar a um efeito tَxico no homem e em animais. Cepas de A. flavus produtoras de aflatoxinas e لcido ciclopiazônico sمo frequentemente isoladas do amendoim, indicando a natural co-ocorrência dessas toxinas neste substrato. Neste estudo, foram isoladas 47 cepas de Aspergillus flavus em grمos e cascas de amendoim durante diferentes fases de maturaçمo do fruto e também durante seu armazenamento. Das cepas isoladas, foram avaliados os potenciais para produçمo de aflatoxinas e لcido ciclopiazônico, em que 91,5% foram produtoras de aflatoxinas e 70% produziram لcido ciclopiazônico, sendo que 63,8% produziram ambas as toxinas e 2,1% nمo produziu nenhuma. A presença de cepas toxigênicas de A. flavus nas amostras de amendoim analisadas indica um risco potencial da contaminaçمo deste produto, caso seja exposto a condiçُes ambientais favorلveis ao crescimento do fungo e produçمo de micotoxinas.

Occurrence of Fungal Species and Mycotoxins from Decayed Sugarcane (Saccharrum officinarum) in Egypt

Seventy-three fungal species belonging to forty-three genera were isolated from 40 samples of Saccharrum officinarum (collected from Naage-Hamadi canal in Qena Governorate, Egypt). Aspergillus, Trichoderma, Mucor and Pythium were the most common genera on the two isolation media. The dominant species of Aspergillus were A. niger, A. flavus, A. ustus, A. terreus and A. wentii. Some species were dominant on 40 g/l sucrose such as Aspergillus niger, A. flavus, Emericella nidulans, Trichoderma viride, Torula herbarum and Mamaria echinoeotryoides, while the dominant species on 10 g/l glucose were Mucor circinelloides, Aspergillus niger, Torula herbarum and Trichoderma viride. Mycotoxins including aflatoxins B1, B2, G1 and G2, zearalenone and diacetoxyscirpenol were detected in the examined samples of Saccharrum officinarum. The mycelial growth of A. flavus, A. niger, Fusarium moniliforme and Torula herbarum decreased with the increase in Dimethoate concentrations, although 25 ppm was less effective than the higher levels of the insecticide (75~200 ppm). Dimethoate stimulated the activity of Go-T in A. niger, F. moniliforme and T. harbarum, while the Go-T activity was inhibited in A. flavus with the Dimethoate treatments.