Materials Required:

 

Cultures:

24-48 hourstryptic soy broth cultures of organisms

 

Media:

Litmus milk broth (pH-6.8)

Skim milk powder 100g

Litmus 0.075g

Distilled water 1,000.0ml

Autoclave at 12lb pressure for 15 minutes

 

Equipments:

Bunsen burner

Inoculating loop

Test tube rack

Marking pen

 

Procedure:

1. Using sterile technique, inoculate each experimental organism into its appropriately labeled tube by means of a loop inoculation. The last tube will serve as a control.

2. Incubate all cultures for 24 to 48 hours at 37˚C.

 

Limitations:

 

1. Litmus milk is a complex medium that can produce a diversity of results. Because of this, litmus milk can give quite unreliable results (i.e., the results often give negative results when something positive should happen). Thus, you would be advised to use litmus milk as a confirmatory test but not a definitive test (except as a last resort).

2. A clot formation is simply recorded as “clot” and cannot clearly differentiate between a clot and curd formation in this medium.