This medium is intended for the cultivation and enumeration (via the Miles and Misra technique) of Lactobacillus spp. from a variety of sources and can be used in conjunction with MRS Agar (KM0080).
This medium is a modification on the formulation developed by de Man, Rogosa and Sharpe.(1)
The peptones, beef extract, yeast extract provides the required carbon, nitrogen and vitamins in this medium. Glucose is a fermentable carbohydrate. 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 magnesium sulphate, manganese sulphate and polysorbate 80 act as growth stimulants.
The medium can be made more specific for lactobacilli generally by lowering the pH to between 5.0 and 5.5.
This has the effect of inhibiting most streptococci that may otherwise grow on the medium and can be readily confused with lactobacilli.
De Man, Rogosa and Sharpe (MRS) Broth
Additional Information
| Shelf Life (days) | |
|---|---|
| Dehydrated Medium Appearance | |
| Dehydrated Medium Colour | |
| Dehydrated PH | |
| Prepared Medium Appearance | |
| Prepared Medium Colour | |
| Prepared PH | |
| Recommended Incubation | Aerobically at 30 ± 1°C for up to 3 days. |
| Container |
Product Description
| Organisms | Ref. No | Result |
| Lactobacillus sakei | NCTC 13842 | Growth |
| Lactobacillus lactis | NCTC 6681 | Growth |
Recommended incubation: Aerobically at 30 ± 1°C for up to 3 days.
Formula*
| g/L | |
| Peptones | 9.75 |
| Yeast extract | 4.0 |
| Beef extract | 8.0 |
| Glucose | 20.0 |
| Potassium phosphate | 2.0 |
| Sodium acetate | 5.0 |
| Ammonium citrate | 2.0 |
| Magnesium sulphate | 0.02 |
| Manganese sulphate | 0.05 |
| Polysorbate 80 | 1.0 |
| Total | 41.0 |
| *Adjusted/supplemented as required to meet performance requirements |
Preparation
Suspend 52.0g of the medium in 1 litre of deionised / purified water.
Allow the medium to soak whilst mixing for 10 minutes.
Dispense into appropriate containers then sterilise at 121°C for 15 minutes.