BIOCHEM YEAST EXTRACT AGAR

Ingredients : gms/lit.
Peptic digest of animal tissue: 5.00
Yeast extract : 3.00
Agar : 15.00
Final pH (at 25°C) : 7.2 + 0.2

Principle : 

Yeast extract and peptic digest of animal tissue provide nitrogenous compounds, vitamin B complex and other growth nutrients.

From the water sample, make a decimal dilution bank with Ringer Solution (B381) and take aliquots to 2 parallel series of plates. Pour the molten, cooled (45°C) Yeast Extract Agar and homogenize with sample. Incubate one of the series of plates at 35°C for 24 hours and the other series of plates at 20-22°C for 3 days. Separate counts are made of the organisms forming visible colonies after 24 hours at 35°C and the organisms forming colonies after 3 days at 20-22°C. Select the plates containing 30-300 colonies.