INITIAL PH AS A DETERMINING FACTOR OF GLUCOSE CONSUMPTION AND LACTIC AND ACETIC-ACID PRODUCTION IN ORAL STREPTOCOCCI

Lactic and acetic acid production was evaluated from six strains of or al streptococci, viz Streptococcus gordonii, Streptococcus mutans, Str eptococcus oralis, Streptococcus salivarius, Streptococcus sanguis and Streptococcus sobrinus cultured in the presence of 1, 5, 10 mM glucos e and without glucose, at initial pH values of 5, 5.5, 6 and 7. S. sob rinus and S. salivarius caused the greatest decreases in pH. At pH val ues of 5 and 5.5, lactic acid and acetic acid production in the specie s tested was discordant with residual glucose levels. Acid production from protein was especially great in S. mutans and S. salivarius.