Snyder Test Agar is used for the estimation ofLactobacillicounts in saliva, and thus the susceptibility of a person to develop dental caries, based on acid production. Glucose is the fermentable carbohydrate and Bromcresol Green, the pH indicator. IfLactobacillusspp. are present in the saliva, Glucose fermentation will cause the pH to drop to 4.4, thus shifting the color from green to yellow. Agar is the gelifying agent.