For the study of pH stability of bacteriophage, the BHI broth was pre-adjusted to a wide range of pH values (pH 2-13) with 1 N HCl and 1 N NaOH. Then, the bacteriophage suspension was inoculated to obtain a final concentration of 106 PFU/ml and incubated overnight at 37 °C. The samples were withdrawn at time intervals and the bacteriophage titers were determined using the double layer agar plate method