<prompt> An improved selective media to carry out the Lactobacillus Colony Test is:Tomato peptone agarRogosas mediumHektoen enteric agarMitis salivarius agar  <response>: 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 patients 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 patients 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 Rogosas medium. The colonies grown on media upon incubation reflect the number of aciduric flora in the patients 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 