Question

A 10-7 is performed on a culture of bacteria in order to perform viable plate counts. From the dilution, *0.1 mL* of solution is plated on solid media, and 66 colonies of bacteria grow on the plate. Assuming each colony came from a single bacterium, how many bacteria are in a single mL of the original culture?

Answer 1

Answer:

$66 * 10^8$ CFU/mL

Explanation:

Given -

a) Number of colonies of bacteria is equal to $66$

b) Total volume of the solution is equal to $0.1$ mL

c) Dilution factor is equal to $10^{-7}$

As we know that

CFU/mL $= \frac{N * DF}{V}$

Where N is the number of bacterial colonies, DF is the dilution factor and V is the volume

Substituting the given values in above equation, we get -

CFU/mL $= \frac{66* 10^7}{0.1} \\= 66*10^8$