de Man, Rogosa & Sharpe (MRS) Agar

//de Man, Rogosa & Sharpe (MRS) Agar

de Man, Rogosa & Sharpe (MRS) Agar

SKU: KM0080 Category:

This medium is used for the cultivation and enumeration of Lactobacillus spp. MRS agar is based on the formulation by de Man, Rogosa and Sharpe.
The peptone, yeast extract and beef extract provides the reuired carbon, nitrogen and vitamin source. Glucose is a fermentable carbohydrate. The magnesium sulphate and manganese sulphate act as growth stimulants. Potassium phosphate is a buffering agent. Selectivity of the medium is achieved through the use of ammonium citrate and sodium acetate, inhibiting microorganisms such as streptococci and moulds. The addition of the surfactant Tween 80 is required to facilitate the uptake of nutrients from Lactobacillus spp.


Additional Information

Shelf Life (days)

Storage Temp (°C)

Dehydrated Medium Appearance

Prepared Medium Appearance

Dehydrated Medium Colour

Prepared Medium Colour

Dehydrated PH

Prepared PH

Product Description

Organisms Ref. No Result
Lactococcus lactis DSMZ 20481 Growth, cream colonies
Lactobacillus sakei DSMA 20017 Growth, cream colonies



Peptone 10.0
Yeast extract 4.0
Beef extract 8.0
Glucose 20.0
Potassium phosphate 2.0
Sodium acetate 4.15
Ammonium citrate 2.0
Magnesium sulphate 0.2
Manganese sulphate 0.05
Agar 10.0
Total 60.4
*Adjusted/supplemented as required to meet performance requirements


Suspend 60.4g of the medium in one litre of deionised / purified water. Add 1.08 ml/l of Tween 80. Allow the medium to soak whilst mixing for 10 minutes. Sterilise at 121°C for 15 minutes with frequent stirring to completely dissolve the medium. Cool to 45-50°C and dispense into appropriate sterile containers.