The stability of bacteriophage ST1 in beverages was studied by monitoring the survival of the bacteriophage in 3 different beverages (soybean milk, coconut juice and orange juice) after bacteriophage inoculation for 24 h (Fig. 3). In soybean milk, no significant change of bacteriophage titer was found throughout the observation period. On the other hand, the decrease of bacteriophage titer was obviously noticed in guava juice and orange juice. In both beverages, the bacteriophage titer drastically decreased from about 6 PFU/ml to an undetectable level within 3 h.