|Malt extract||30 g|
|Distilled water||1 liter|
Boil to dissolve ingredients. Avoid overheating, which causes softening of agar and darkening of medium color. Autoclave 15 min at 121°C. Dispense 20-25 ml into sterile 15 × 100 mm petri dishes. Final pH, 5.5 ± 0.2.
For cosmetics use
Cool medium to 47-50°C after autoclaving. Dispense 4 ml stock filter-sterilized chlorotetracycline HCl solution (1 g/100 ml) per liter of medium to yield final concentration of 40 ppm chlorotetracycline HCl. Mix thoroughly and dispense 20 ml portions into 15 × 100 mm petri dishes.
Original Source: Bacteriological Analytical Manual, 8th Edition, Revision A, 1998.