Effect of powder thymus as the carrier of bacteria probiotic Lactobacillus acidophilus and Bifidobacterium bifidum in milk and yoghurt

The use of natural antimicrobial compounds indenting herbal medicine and flavorings in preserving foods has been widely devoted. These compounds other than antimicrobial characteristic have antioxidant and flavoring characteristics. The other hand probiotic products by reducing the risk of heart attacks and recovering favorable microbial flora of digestive tract have an extraordinary effect on consumer's health status. This survey was done in order to evaluate the effect of thymus on lactobacillus acidophilus and Bifidobacterium bifidum as the starter bacteria of probiotic yoghurt. To determine the effect of thymus different doses (0%, 0.03%, 0.06% and 0.09%) on the growth of probiotic bacteria, Bifidobacterium bifidum and lactobacillus acidophilus in the first stage (milk) and the second stage, 0.33 grams of lyophilized Bifidobacterium bifidum and lactobacillus acidophilus separately was added to one liter of sterilized low fat milk. In on other experiment, a mixture of two bacteria, in an amount of 0.165, was done according to the above steps. The samples were evaluated on the basis of pH, acidity and microbial count in the warm holding and preservation periods. In the tenth day of production the products were evaluated under organoleptic tests. The results of questionnaires were and used in the descriptive analytic test and by the use of SPSS software. The results showed that in the samples containing two bacteria we have got the best results related to the taste, preservation and color. Bioavailability of probiotie bacteria was counted by the use of direct counting method. In a 15 day period, the number of bacteria was decreased and also no statistically meaningful difference was observed between the control samples and the samples containing different concentrations of thymus.