Question

What is the concentration of a suspension that grew 27 colonies on a plate made with 0.1ml from a culture with a dilution of 1:10,000?

Answer 1

Answer:

2700000 CFU/ml

Explanation:

Dilution is of 1:10000 so if 27 colonies were observed :

27 * 10000 = 270000 CFU or colony forming units are present

But 0.1 ml of culture has been used so:

CFU/ml would be 270000 * 10 = 2700000 CFU/ml

Hence concentration of suspension is 2700000 CFU/ml