To determine the thermal stability of bacteriophage, 5 ml of BHI broth was preheated to a desirable temperature, ranging from 50 to 80°C. Then, the bacteriophage suspension was inoculated into each of the preheated BHI broth to obtain a final concentration of 106 PFU/ml. After heating at the assigned temperatures for 3 min, the samples were placed in an ice bath. Residual titers of all samples were determined by using the double layer agar plate method.