Tarhana is popular traditional Turkish fermented wheat and yoghurt based product. In the study, survival of Escherichia coli O157:H7 was investigated during the fermentation of tarhana produced with different spices. Additionally, lactic acid bacteria (LAB) and yeast population were enumerated during the four days of fermentation. The pH values of the samples gradually decreased from 5.75 to 3.75-3.84 at fourth day. Escherichia coli O157:H7 could not be detected at the end of the second day of fermentation in none of the samples. The decrease in the pH might be responsible for the antibacterial effect at the end of the second day of fermentation. LAB counts and yeast population were ranged between 10(6) and 10(7) CFU/g. The tarhana fermentation for the survival of E. coli o157:H7 proves microbiological safety in the products because of the low pH and high LAB counts, and the other pathogenic bacteria may also be inhibited during the fermentation. The inhibitory effects of the spices in tarhana samples were almost the same with the control group.