| Congresso Brasileiro de Microbiologia 2023 | Resumo: 382-1 | ||||
Resumo:One of the main problems related to the production and commercialization of orange juice is the spoilage by microorganisms. Due to the low pH of the beverage, it is susceptible to the presence of filamentous fungi, yeasts, and lactic acid bacteria. To minimize these problems, the orange juice is subjected to the use of heat treatment. Among the spoilage fungi, the genus Paecilomyces is known for presenting heat-resistant representatives, in addition some strains are resistant to sanitizers. Yeasts, such as Wickerhamomyces, are also a problem, especially because of their ability to form biofilms. This study aimed to verify the potential formation of individual and combined biofilms of strains of Paecilomyces variotti and Wickerhamomyces anomalus, previously isolated from a juice processing line and associated spoiled products, from a company located in the interior of São Paulo, and to verify the susceptibility of filamentous fungi and yeasts to sanitizers used in the food industry. To evaluate the biofilm formation, 100 µL of P. variotti (1*105 spores/mL) and W. anomalus (1*108 spores/mL) combined and separated were inoculated in 96-well plates and incubated for 24, 48 and 72 hours. Subsequently, the plates were washed and the adhered biofilm was stained with crystal violet (0.1%), and the OD quantified at 570 nm. Additionally, the biofilm was broken by using PBS and a 35 kHz ultrasonic bath, and the recovered cells plated onto MEA medium by the surface technique. For the sanitizer analysis, the biofilm formed was subjected to treatment with Vorteex sanitizers (0.05%, 0.1%, and 0.3%), Vorteex es (0.015%, 0.06%, and 0.12%) and chlorine (200 ppm, 50 ppm, and 12.5 ppm), and after the period of incubation and neutralization, an aliquot of 10 µl was added to a plate of MEA medium and incubated at 25ºC for 48 hours. The results showed that the combined strains of P. variotti and W. anomalus showed better biofilm formation at 72 hours. In contrast, individual filamentous fungi strains showed better biofilm formation at 48 hours and yeasts at all tested periods. Regarding susceptibility to sanitizers, all tested strains of P. variotti and W. anomalus combined showed resistance to the tested products. However, when the biofilm was formed by the individual strains, the microorganisms showed resistance only to chlorine-based sanitizers. Only one strain of P. variotti exhibited resistance to the sanitizer based on peracetic acid plus peroxide (0.015%). These results indicate the possible persistence of these microorganisms in processing lines, in addition to pointing out that filamentous fungi agglomerate in biofilms formed by yeasts, being dragged more easily, thus leading to future problems of juice spoilage. Palavras-chave: filamentous fungi, yeasts, biofilm formation, sanitizers Agência de fomento:CAPES | |||||