MRS Agar recommended for the cultivation of lactobacilli.

Composition g / l

Peptic Gulf 10.00

Extract of meat 8,00

Yeast extract 5,00

Ammonium citrate 2.00

Sodium acetate 5.00

Glucose 20.00

Magnesium sulfate 0.20

Manganese sulfate 0.05

Potassium dihydrogen phosphate 2.00

Agar-agar 12.00

Appearance:

A bottle of 500 g of dry medium.

Method of cooking:

Pour 64.25 g of dry medium into 900 ml of distilled water. The mixture is boiled to the full

dissolving ingredients. Bring the volume of the liquid to 1000 ml, check the pH and, if necessary,

adjust the value to 5.7 ± 0.2, using a 10% solution of NaOH or a 10% solution of HCl.

Sterilize in an autoclave at 121 ° C for 15 minutes.

Density of the finished medium:

The medium corresponding to the density of 1.2% agar gel is formed.

Color and transparency of the finished medium:

Ready medium has a light amber color, lightly opalestsuetsya if in cups Petri then

gel is formed.

Acidity of the medium:

At 25 ° C, an aqueous solution (6.71% w / v) pH 5.7 ± 0.2.

Principle and score of the result:

• Used for the selection and calculation of lactobacilli from meat and meat products.

The medium is selective in connection with changes in pH; lactobacilli carry low pH,

unlike other bacteria of lactic acid.

• Peptone, Glucose, Yeast Extract and Meat Extract Provide Necessary Nutrition

substances; Polisorbatul 80 provides the necessary essential fatty acids needed

for metabolism, and ammonium citrate and sodium acetate inhibits the development of streptococci and

other microorganisms.

• The presence of carbon dioxide stimulates the development of lactic acid bacteria.

• After inoculation of the medium with the test sample, they are placed in an incubator

for 24-48 hours at a temperature of 35-37 ° C.

Results:

Microorganism Streams (ATCC) Growth

Lactobacillus acidophilus (19992) abundant

Lactobacillus fermentum (9338) abundant

Lactobacillus plantarium (8014) abundant

Lactobacillus lactis (19435) abundant