M.R.S. AGAR Low pH 500 grams/bottle

MRS Agar Low pH is a selective medium that supports the good growth of lactobacilli in general. The medium is apt for the growth of lactic acid bacteria, including Lactobacillus, Pediococcus and Leuconostoc. Ammonium citrate, at a low pH, inhibits most microorganisms, but allows the growth of lactobacilli. Dipotassium phosphate and sodium acetate are buffer agents to maintain a low pH. Tween 80 is an emulsifier. Manganese and magnesium sulfates are sources of ions and sulfate. Casein peptone and beef extract provide nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Dextrose is the fermentable carbohydrate. Bacteriological agar is the solidifying agent. The growth of some lactobacillus strains is inhibited at a pH higher than 6,0 and it is necessary to acidify the medium to favor the growth. With a pH of 5,7±0,1, this medium favors the growth of these strains. Normative ISO 15214 recommends this medium for the enumeration of mesophilic lactic acid bacteria Colony count technique at 30 ºC.