Fungos do gênero Aspergillus isolados de amêndoas de cacau do estado de Rondônia

Microorganisms can develop during primary processing (harvesting, breaking, fermentation, drying and storage) of cocoa beans. In tropical regions the fungi of the Aspergillus genus are considered important. Its presence should be investigated since it is related to the decrease in quality and, therefore, a health risk to consumers, due to the possible production of mycotoxins. In this context, this study was performed in order to investigate the presence of species of the Aspergillus genus in cocoa beans in the state of Rondônia, Brazil; verify the toxigenic potential; study the effect of geographical origin on the incidence of toxigenic and non- toxigenic fungi species; and analyze the incidence of the species and its relation with the practices of fermentation, drying and storage. Fungi isolation from the collected cocoa beans was performed by direct plating in DRBC medium. Aspergillus carbonarius were evaluated for the quantification of OTA by High Performance Liquid Chromatography (HPLC). To estimate the probability of occurring species of the Aspergillus genus in Rondonia, we used the logistic regression technique. A total of 185 fungi of the Aspergillus genus were identified belonging to Sections Nigri (A.niger, A. carbonarius, A. niger Aggregate, A. foetidus, A. japonicus, A. aculeatus and A. tubingensis) and Flavi (A. flavus and A. oryzae). Of the A. carbonarius tested, 79.41% produced OTA at levels ranging from 0.08 to 44.09 μg/g and 3.13% of the A. niger showed potential to produce OTA. A significant percentage (83.33%) of A. flavus was capable of producing AFs B1 and B2. The total occurrence of fungi species of the Aspergillus genus differs depending on the geographical coordinates and temperature showing higher probability of occurrence in cocoa beans from the municipalities located south of the state of Rondônia, and the probabilities of occurring toxigenic fungi were similar in all studied regions with the primary processing practices exerting effect on the incidence of toxigenic fungi in cocoa beans.