An improved selective media to carry out the Lactobacillus Colony Test is:
Lactobacillus Colony Test:
The oldest and the most widely used microbiological method for assessing the caries activity is the Lactobacillus colony count. This method, measures the number of aciduric bacteria in a patient’s saliva by counting the number of colonies which appear on tomato peptone agar plates, a selective medium with pH 5.0, after inoculation of the patient’s saliva and incubation. An improved selective media with an acidic pH having high amounts of acetate, salts and lower surface tension that is highly selective for growth of Lactobacillus is the Rogosa’s medium. The colonies grown on media upon incubation reflect the number of aciduric flora in the patient’s saliva. 
Note: 
Hektoen enteric agar (HEK, HE or HEA) is a selective and differential agar primarily used to recover Salmonella and Shigella from patient specimens. HEA contains indicators of lactose fermentation and hydrogen sulfide production; as well as inhibitors to prevent the growth of Gram-positive bacteria. It is named after the Hektoen Institute in Chicago, where researchers developed the agar.
Mitis Salivarius Agar (MSA), a selective streptococcal medium with increased concentration of sucrose (20%) and 0.2 U bacitracin per ml to suppress the growth of most non S.mutans colonies. Agar plates are incubated at 37° C for 48 hours; 95% N2 - 5% CO2. 
Essentials of preventive and community dentistry 
Soben Peter 
5th edition
Tomato peptone agar
Rogosa’s medium
Hektoen enteric agar
Mitis salivarius agar