LACTIC ACID PRODUCTION IN SALIVA

¹ Chemistry Department, University of Toronto, Toronto, Canada

Lactic acid production in saliva seems to be a poor criterion for lactobacillus concentration since zero-count salivas produce considerable amounts of lactic acid, and in the few cases studied there is no apparent relation between lactobacillus count and lactic acid production.

Quite low concentrations of glucose (0.1 per cent) are sufficient for lactic acid production. The optimum pH for lactic acid production is 6.5. The addition of urea to saliva-glucose mixtures, even though it keeps the pH of the incubation mixture above 7.0, does not inhibit lactic acid production and in this experiment even enhanced somewhat the lactic acid production.