Does Thyme Essential Oil (Zataria Multiflora) Improve Durability, the Taste and Nutritional Value of Doogh?

Introduction: Diseases caused by the consumption of bacteria-contaminated foods have been of great importance in public health. Therefore, control of dairy product contamination with coliforms is a concern for the durability of dairy producers. Control of the contamination by natural products may have dual action; nutritive value and natural antibiotics. In this study, the antimicrobial activity of thyme essential oil against Escherichia coli O157: H7 in doogh (Iranian fermented dairy drink) was examined and the MIC and MBC were determined. Methods: Antimicrobial activity of thyme essential oil was examined using different concentrations (0, 30, 60, 90, and 120 μl/ml) against bacteria with a density of 105CFU/ml during the 60-day at 4 °C. Moreover, the effect of different concentrations of essential oils on the taste of doogh was also studied. Taste evaluation was performed based on 5 points hedonic test to evaluate the effect of Thyme oil on the sense of taste. Duncan software was used to determine the difference between test and control groups at a confidence level of 5%. The SPSS software was also used for statistical analysis. Results: All concentrations of thyme essential oil could stop the growth of bacteria (P 0.05). The inhibitory effect of oil increased with increasing concentration and time. Based on the results of sensory (taste) evaluation, treatment 2 (containing 60 μl/ml of essential oil of thyme) was selected as the best treatment. Conclusion: Thyme essential oil can be used as a natural preservative with a positive impact on taste and nutritive value.