Product number: NCM0035

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 & yeast extracts while Tween® 80, magnesium and manganese sulfates act as growth stimulants. Selectivity against streptococci & molds 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, sterilization 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.


Formula Liter
Peptone 10.0 g/L
Yeast Extract 5.0 g/L
Beef Extract 10.0 g/L
Glucose 20.0 g/L
Dipotassium Phosphate 2.0 g/L
Sodium Acetate 5.0 g/L
Triammonium Citrate 2.0 g/L
Magnesium Sulfate 0.2 g/L
Manganese Sulfate 0.05 g/L
Tween 80 1.08 g/L
Agar 15.0 g/L

Final pH: 6.4 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.


  1. Suspend 70 grams of the medium in one liter of purified water.
  2. Heat with frequent agitation to completely dissolve the medium, if necessary.
  3. Autoclave at 121°C for 15 minutes.
  4. Cool to 45-50°C.
  5. If acidified medium is required, adjust pH aseptically prior to pouring.

Product was previously known as Acumedia Product: 7543 Lactobacilli MRS Agar; and LabM Product: LAB093 M.R.S Agar - de Man, Rogosa and Sharpe Agar

Order Details

Product # Product Description
NCM0035A Lactobacilli MRS Agar, 500 g
NCM0035B Lactobacilli MRS Agar, 5 kg
NCM0035C Lactobacilli MRS Agar, 10 kg
NCM0035D Lactobacilli MRS Agar, 25 kg (European only size)
NCM0035E Lactobacilli MRS Agar, 50 kg (US only size)

Reference Material

NCM0035 - Lactobacilli MRS Agar, Safety Data Sheet [Danish] [Dutch] [English] [EU English] [Finnish] [French] [German] [Italian] [Spanish, Mexico] [Swedish]
NCM0035 - Lactobacilli MRS Agar, Technical Specifications Sheet [English]

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