This monograph has been assessed by members of the IUMS–ICFMH Working Party on Culture Media and given ‘Approved’ status.

Rogosa agar in the original version (Rogosa et al., 1951) is primarily a selective medium for the cultivation of lactobacilli (genus Lactobacillus). A high acetate concentration and low pH effectively suppress other bacteria, but also many strains of other lactic acid bacteria. The modification of the pH to 6.2 instead of 5.5 alters the selectivity of the medium for the whole group of lactic acid bacteria (ISO, 1984; Reuter, 1985).

Suspend all the ingredients, except the acetic acid, in cold water and heat to boiling to dissolve completely. Add the glacial acetic acid and mix thoroughly. Adjust pH to 6.2 at about 50°C. Heat to 95°C for 3 min. Do not autoclave. Cool to 45°C and distribute into Petri dishes.