Application

MRS Agar is a medium is suitable for the detection, isolation, and cultivation of lactobacilli and other lactic acid bacteria from food and beverages.

General description

MRS Agar is a medium used for the cultivation of lactobacilli. It is a modified medium based on the highly nutritious properties of tomato juice. The addition of magnesium, manganese, and acetate, together with polysorbate, provides an improved medium for the growth of lactobacilli, including very fastidious species such as Lactobacillus brevis and Lactobacillus fermentum. The quality of the peptones, in addition to the meat and yeast extracts, combine all the necessary growth factors that make MRS medium one of the best media for the cultivation of lactobacilli. As the selectivity of this medium is low and contaminants tend to grow, subculturing in a (double layer) solid medium and then in broth is recommended to increase selectivity. In many cases, growth is encouraged by incubation in a CO₂-enriched atmosphere.