Different yoghurt products which contain probiotics as antipathogenic bacterial growth were studied in Al Hasa market, Saudi Arabia. Three types of yoghurt were selected in addition to the control (traditional yoghurt). It was found that the control and the first type probiotic yoghurt exhibited the lowest pH values when compared to all other treatments. Also, it was found that the control had the highest amount of the lactic acid and the lowest amount of the acetic acids significantly (P≤0.05) compared to all other treatments. However, the first and the third types had the highest amount of the acetic acid significantly (P≤0.05) compared to all other treatments. In addition to that, it was found that the greatest reduction in the Escherichia coli  was in both the control and the second type products. Also, it was found that the greatest reduction in the salmonella count was in the control and the first type products. In a storage life study, it was found that a significant reduction in the Escherichia coli was happened during five days                                             storage period and completely disappeared after 10, 15 days storage periods for the control and the first type products, respectively. Also, it was found that a significant reduction in the salmonella count was happened during the 5 and 10 days storage periods for both the control and the first type products, respectively. While, insignificant reduction in the salmonella count was found in other two types (type two and three) during the first period of the storage. However, this reduction was changed to become significant during the 10 and 15 days of storage periods. The final salmonella count was found to be 4.45 and 5.58 log₁₀ /ml of yoghurt for the third and the second types, respectively. Finally, by comparing the results it was found that the control and the first type products had the highest reduction in the salmonella count compared to all other treatments during the 10 and 15 days of storage periods. These differences among the different treatments could be due to the variations in the organic acids contents and the different pH values.