LBS (Lactobacillus Selection) Agar is used for the selective isolation and enumeration of lactobacilli.

Principles Peptone, yeast extract and dextrose supply nitrogenous and carbonaceous compounds for the support of bacterial growth. Polysorbate 80 is a source of growth factors, since it supplies fatty acids required for the metabolism of lactobacilli. The ammonium citrate and sodium acetate inhibit the growth of many organisms, including streptococci, molds and members of the oral microbial flora other than lactobacilli, and restrict swarming on the agar medium.9 The low pH, due to the addition of acetic acid, also is inhibitory for other bacterial flora and favors the isolation of lactobacilli.

• BD Difco LBS Agar Technical Data Sheet