DSMZ 78b . CHOPPED MEAT MEDIUM (N2/CO2)

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Equipment needed: Autoclave Filter Gassing station Hungate tubes

Final gas composition: 80 % N2 20 % CO2 read more

Final pH: 7.0

Select a strain (optional):

ml
Compound Amount Unit
Ground beef
(fat free)
500.0 g
NaOH
(1 N)
25.0 ml
Casitone 30.0 g
Yeast extract 5.0 g
K2HPO4 5.0 g
Sodium resazurin
(0.1% w/v)
0.5 ml
L-Cysteine HCl x H2O 0.5 g
Distilled water 1000.0 ml
1 Use lean beef or horse meat. Remove fat and connective tissue before grinding. Mix meat, water and NaOH, then boil for 15 min with stirring. Cool to room temperature, skim fat off surface, and filter, retaining both meat particles and filtrate. To the filtrate add Casitone, yeast extract, hydrogen phosphate and resazurin, then add water to a final volume of 700 ml. Sparge medium with 80% N2 and 20% CO2 gas mixture for 30 - 45 min to make it anoxic, then add cysteine and adjust pH to 7.0. Dispense medium under same gas atmosphere into anoxic Hungate-type tubes containing meat particles (use ca. 7 ml liquid medium for 1 - 2 g meat particles), then autoclave at 121°C for 20 min.
2 In some cases (as indicated in the catalogue) the addition of Haemin and Vitamin K1 or Vitamin K3 is necessary. Add to 1000 ml of medium after autoclaving:
Haemin solution
optional
10.0 ml
Vitamin K1 solution
optional
10.0 ml
Vitamin K3 solution
optional
1.0 ml

Haemin solution #

100
Compound Amount Unit
Haemin 50 mg
NaOH
(1 N)
1 ml
Distilled water 100 ml
1 Dissolve 50 mg haemin in 1 ml 1 N NaOH; make up to 100 ml with distilled water and filter sterilize. Store refrigerated.

Vitamin K1 solution #

20
Compound Amount Unit
Vitamin K1 0.1 ml
Ethanol
(95 %)
20.0 ml
1 Dissolve 0.1 ml of vitamin K1 in 20 ml 95% ethanol and filter sterilize. Store refrigerated in a brown bottle.

Vitamin K3 solution #

100
Compound Amount Unit
Vitamin K3 5 mg
Ethanol
(95%)
1 ml
Water 100 ml
1 Dissolve 5 mg vitamin K3 in 1 ml 95% ethanol, dilute to 0.05 mg/ml in water and filter sterilize. Store refrigerated in a brown bottle.