The study by Terzaghi and Sandine (1975) aimed to improve the growth conditions for lactic streptococci and their bacteriophages by incorporating β-disodium glycerophosphate (GP) into a complex medium. The resulting medium, named M17, was found to enhance the growth of various lactic streptococcal strains compared to other media lacking GP or lactic broth. The increased buffering capacity of M17 prevented pH drops below 5.70, which is crucial for the growth of these bacteria. Additionally, M17 was effective in isolating mutants lacking lactose-fermenting ability and demonstrated superior performance in isolating and distinguishing between lactic streptococcal bacteriophages. The medium also preserved the acid-producing activity of lactic streptococci in milk, even after daily subculturing. The study concluded that M17 is a valuable medium for both the growth of lactic streptococci and the study of their bacteriophages, offering improved conditions for research and practical applications.The study by Terzaghi and Sandine (1975) aimed to improve the growth conditions for lactic streptococci and their bacteriophages by incorporating β-disodium glycerophosphate (GP) into a complex medium. The resulting medium, named M17, was found to enhance the growth of various lactic streptococcal strains compared to other media lacking GP or lactic broth. The increased buffering capacity of M17 prevented pH drops below 5.70, which is crucial for the growth of these bacteria. Additionally, M17 was effective in isolating mutants lacking lactose-fermenting ability and demonstrated superior performance in isolating and distinguishing between lactic streptococcal bacteriophages. The medium also preserved the acid-producing activity of lactic streptococci in milk, even after daily subculturing. The study concluded that M17 is a valuable medium for both the growth of lactic streptococci and the study of their bacteriophages, offering improved conditions for research and practical applications.