MRS Broth

MRS Agar is a selective culture medium used for cultivation and isolation of lactobacilli from different materials, such as the oral cavity, dairy products, food, and fecal samples. It is a modified version of the original de Man, Rogosa, and Sharpe formulation. Crucial components of the medium have specialized roles: glucose is the main source of carbohydrates and energy, while peptone and yeast extract give necessary supplies of carbon and nitrogen. Tween 80 facilitates the consumption of fatty acids, which increases the medium’s ability to support Lactobacillus metabolism. As selective agents, sodium acetate and ammonium citrate prevent the formation of contaminants like mold and streptococci.
Since many species show growth inhibition at higher pH values, it is frequently required to modify the medium’s pH down below 6.0 to optimize growth conditions for specific Lactobacillus strains.

Storage
Keep the container of dehydrated powder and prepared culture medium at 2 to 8 °C.