Óleo essencial de tomilho (Thymus vulgaris): Atividade antimicrobiana contra fungos isolados de alimentos e aplicação como componente ativo em filme de acetato de celulose

Abstract

The development of fungi in food, in addition to causing considerable sensory changes, also poses a potential health risk due to the possible presence of mycotoxins. Seeking to minimize the risks of microbial contamination in food, and the growing demand for the use of more natural and sustainable compounds in the food industry, the development of active and biodegradable packaging is highlighted. Therefore, the aim of this study was to evaluate the antimicrobial activity of thyme (Thymus vulgaris) essential oil - OET against fungi isolated from food, as well as to evaluate its potential as an active component in cellulose acetate film. The antifungal action of OET was evaluated in vitro, through the methodologies of diffusion in agar, microatmosphere, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC), with fungal isolates from cheeses sold in the region of Pelotas-RS. The isolated fungi were molecularly identified as Penicillium crustosum, Aspergillus flavus and Fusarium oxysporum. In the antifungal action tests of diffusion in agar and micro-atmosphere, the OET showed an inhibitory action against all tested fungi, with inhibition zone greater than 10 mm. Peniculiium crustosum isolate had a MIC of 1 µL/mL and a CFM of 3 µL/mL, while Aspergillus flavus had a MIC of 0.8 µL/mL and a CFM of 4 µL/mL and Fusarium oxysporum isolate had a MIC of 0 .7 µL/mL and CFM 3 µL/mL In the in vitro tests of the active film activity, the inhibition on the Penicillium crustosum isolate stands out, which showed a greater sensitivity to the active film and Fusarium oxysporum with lower sensitivity, when compared to the other fungal isolates. It is concluded that OET has potential antifungal action against the different species tested, and when added to a cellulose acetate film, it was effective in fungal control, mainly against Fusarium oxysporum.