Essential Oils against Salmonella Spp. in the Food

Abstract

The main goal of the study was to determinate the antimicrobial effect of various concentrations of basil and thyme essential oils (1. 2.5 and 5%) on growth of two strains of bacteria from the genus Salmonella: Salmonella enterica subsp. enterica subsp. ebterica serovar Enteritidis (D) ATCC 13076 - reference strain (S. enteritidis RS)  and Salmonella enteritidis (group D) - epidemic strain (S. enteritidis ES). The bacteria were inoculated in pasta with eggs, in conditions of a simulated industrial process of production and in laboratory conditions, inoculated in flour and chicken eggs, used as raw materials for preparing the dough for making pasta with eggs (the samples were exposed at 37⁰C and 46⁰C: the temperature of 37⁰C was chosen because according to the literature data the ideal temperature for growth of bacterial cells of the genus Salmonella is 35 - 37⁰C and 46⁰C was pasta drying temperature applied in the industrial production of pasta and applied in the first phase of research in conditions of simulated production process).

Regardless from the concentrations of added basil and thyme essential oils in the samples. the number of bacterial cells S. enteritidis RS and S. enteritidis ES was gradually decreased in each successive stage of the production process from the control to the target samples. The influence of the added concentrations of essential oils of basil and thyme in pasta and the simulated process of pasta production, showed a high statistical significance at level p < 0.001 on the number of bacterial cells of S. enteritidis RS and S. enteritidis ES in the pasta, while their interaction showed a statistically significant influence on the level p < 0.01. Statistical models for the influence of the concentrations of basil and thyme essential oils on the number of bacterial cells of S. eteritidis RS and S. enteritidis ES in basic solution (physiological solution + various concentrations of essential oils of basil and thyme) in flour and eggs with micellar solution, as well as their interaction, revealed a statistically significant effect on the number of bacterial cells.