LITMUS MILK MEDIUM

Technical Data #2899a / 2013.07.09

Litmus Milk Broth is a liquid medium used to aid in species differentiation primarily from the genus Clostridium, of Streptococcus bovis from Streptococcus equinus, maintenance of lactic acid bacteria associated with dairy products and detection of Bacillus cereus in foods.

 


 

FORMULA
in grams per liter purified filtered water

Skim Milk

100,0

Litmus

0,75

pH 6,8 +/- 0,2 à 25º C

This approximate formula may be adjusted and/or enriched to obtain best results.


PRECAUTIONS
This medium is for IN VITRO diagnostic use only.


STORAGE
Store prepared media at 2-8º C protected from direct light and dehydrated powder, in a dry place in tightly-sealed containers at 2-25º C.


SIGN OF DETERIORATION
Media should not be used if the expiry date has passed. Prepared media should not be used if there are signs of contamination (evaporation or discoloration). Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 100,8 g in 1000 ml of purified water. Heat gently into solution. Mix thouroughly and dispense into culture tubes. Sterilize at 118º C for 15 minutes. AVOID OVERHEATING.


PROCEDURE
Before inoculation, boil for 2 minutes and bring prepared medium at room temperature.

  1. Inoculate with 1-2 similar colonies from an overnight growth. For anaerobes, add 1-2 ml sterile mineral oil.
  2. Incubate at 35º C for up to 14 days before discard, with loosened caps.
  3. Examine daily for results.


QUALITY CONTROL

Expected results after 7 days at 35ºC

Organisms

ATCC

Growth

Clostridium perfringens

13124

Acid, w/ gas


Pseudomonas aeruginosa

27853

Peptonized

Clostridium sporogenes

11437

Acid, clot, proteolysis

Enterococcus faecalis

29212

Acid, clot


LIMITATIONS OF METHOD
During storage, medium may show a layered coloration due to the oxidation of the top of the liquid, boiling during 2 minutes will drive off oxygen. This is only a part of the identification. Others tests may be required.


REFERENCES

  1. Lennette, E.H., Ballows, A., Hausler, W.J.Jr., and Shadomy, H.J. Manual of Clinical Microbiology. 4th ed. 1985 Washington D.C.: American society for Microbiology.
  2. Mac Faddin, Jean F. 1985 Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria. Vol. I, Baltimore, MD.: Williams & Wilkins.
  3. Webster, G.F., K.J. McGinley 1977 Use of litmus milk agar for presumptive identification of cutaneous propionibacteria J. Clin. Microbiol. 5(6):661.


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-3409
     
Prepared media    
Tubes 16x125 mm, 5 ml 10/pkg 2899

 


 

 

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