Uso de óleos essenciais de especiarias para controle de coliformes em linguiça toscana

Abstract

The food products deterioration by pathogenic microorganisms is a major problem especially in meat industries. Escherichia coli is a facultative anaerobic bacteria of intestinal origin, and is a cause of concern in the meat industry. The use of essential oils as inhibitors of growth of spoilage and pathogenic microorganisms is a good natural choice contributing for the reduction of food deterioration. This study aimed to evaluate twenty (20) in vitro activities of E. coli strains retrieved from the collection of bacteria of Laboratório de Pesquisas Micológicas of the Universidade Federal de Santa Maria (UFSM). The microdilution methodology was applied following the M31-A3 technique protocols. Thymol and the essential oil of thyme (Thymus vulgaris), cinnamaldehyde and the essential oil of cinnamon (Cinnamomum zeylanicum), carvacrol and the essential oil of oregano (Origanum vulgare) were the main oils used along with their components. In these tests, the essential oils presented better results than its constituents. Besides, in vitro tests had been carried out with the same isolate in order to evaluate the antimicrobial activity of the thyme, cinnamon and oregano essential oils. The geometric means of the MIC (minimum inhibitory concentration) and MBC (minimal bactericidal concentration) for the essential oils of oregano, cinnamon and thyme did not show relevant differences (p > 0.05). Afterwards, the activities of these oils were evaluated against the growth of coliforms in the Toscana sausage mass. The samples (Toscana sausage mass added with the essential oils) to the concentrations of 8000 μg.ml-1 , 3200 μg.ml-1 , 400 μg.ml-1 , 200 μg.ml-1 , with the addition of the strain (Escherichia coli) 103 U C T 5 C 5 20 e 30 days using the 3M technique Petrifilm dish for counting the E.coli and coliforms (AOAC 991.14). During the 30 days storage of the Toscana sausage mass, there was a reduction in the counting of total coliforms and the thermotolerant coliforms with addition of essential oils in different concentration levels. The sensory analysis of the Toscana sausage added with the essential oils of cinnamon and oregano in the concentration of 200 μg.ml-1 and 400 μg.ml-1 were considered as acceptable by the consumers.