Lactobacilli MRS Agar is used for the cultivation of lactobacilli and is not intended for use in the diagnosis of disease or other conditions in humans. MRS Agar is a medium for the cultivation and enumeration of Lactobacillus spp. Originally developed in 1960 by de Man, Rogosa & Sharpe, the medium is suitable for most lactic acid bacteria and is intended as a substitute for Tomato Juice Agar. When acidified to pH 5.4 MRS Agar can be used to enumerate Lactobacillus bulgaricus in yogurts. Nutrition is provided by a mixture of carefully selected peptones, glucose, beef and yeast extracts while Tween® 80, magnesium and manganese sulfates act as growth stimulants. Selectivity against streptococci and moulds is provided by ammonium citrate and sodium acetate. Used at low pH, ammonium citrate allows growth of lactobacilli while inhibiting a number of other microorganism groups. Occasionally, sterilisation of this medium at 121°C for 15 minutes, in some autoclaves, may cause the pH to fall outside of the specified pH limits 6.4 ±0.2. In these rare cases, adjustment of the medium using acetic acid or sodium hydroxide is recommended.

• Analyte: Lactobacillus spp.
• Platform: dehydrated culture media
• Formula: peptone 10.0g/L, yeast extract 5.0g/L, beef extract 10.0g/L, glucose 20.0g/L, dipotassium phosphate 2.0g/L, sodium acetate 5.0g/L, triammonium citrate 2.0g/L, magnesium sulfate 0.2g/L, manganese sulfate 0.05g/L, Tween 80 1.08g/L, agar 15.0g/L
• Grams per litre: 70.00
• Litres per 500g; 7.00
• Plates per 500g: 390.00