|Beef extract||1 g|
|Phenol red (1% solution in 95% ethanol)||2.5 ml|
|Distilled water||900 ml|
Heat with agitation to dissolve agar. Adjust pH so that value after sterilization is 7.2 ± 0.2. Dispense 225 ml portions to 500 ml Erlenmeyer flasks. Autoclave 15 min at 121°C. Cool to 50°C. MYP agar is commercially available from Difco.
Polymyxin B solution, 0.1%
Dissolve 500,000 units polymyxin B sulfate in 50 ml distilled water. Filter-sterilize and store in the dark at 4°C until needed.
Egg yolk emulsion, 50%
(see M51). Also available from commercial suppliers.
To 225 ml melted base add 2.5 ml polymyxin B solution and 12.5 ml egg yolk emulsion. Mix and dispense 18 ml portions to sterile 15 × 100 mm petri dishes. Dry plates at room temperature for 24 h before use.
Original Source: Bacteriological Analytical Manual, 8th Edition, Revision A, 1998.