Ozonização de Castanhas de Caju e do Brasil para o controle de fungos filamentosos

Abstract

The contamination of chestnuts by filamentous fungi, which produce mycotoxins, is considered a serious public health problem, which makes its control essential to obtain a quality and safe product for the consumer. Thus, the objective of this research was to evaluate the fungicidal effect of ozone against filamentous fungi isolated from cashew nuts and Brazil nuts. For this, 10 samples of chestnuts commercialized in bulk were used in the municipality of Fernandópolis – SP, from october to december, 2019. The search for filamentous fungi was carried out using the serial dilution method and plating on Potato Dextrose Agar. The dishes were incubated at 25ºC for 5 days, then the colony counts and genera identification were performed by observing the macroscopic characteristics and micromorphological structures. To test the effectiveness of ozone, 25g of chestnuts were diluted in 225 mL of 1% peptone water. This material was exposed to ozone at different times (5, 10, 15, 20, 25 and 30 minutes). In each time interval, 0,1 mL aliquots were inoculated in triplicate, in Petri dishes containing Potato Dextrose Agar, to determine the minimum fungicidal concentration (MFC). After tabulation of the collected data, two statistical analysis functions were performed: descriptive and inferential. The data were replicated in an absolute and relative way. In the inferential scope, the test Paired T Test was used. The fungal microbiota was detected in all samples analyzed, and in 70% of these, more than one genus was isolated. The genera were isolated: Aspergillus, Penicillium, Cladosporium, Curvularia, Absidia and Rhizopus. With the use of ozone, an average reduction of 96.5% of fungi can be seen in up to 30 minutes of exposure. It was concluded that ozonation was efficient in inactivating filamentous fungi and, consequently, in preventing mycotoxin synthesis.