Question

the standard plate count method is performed with dilutions of the original sample. 0. 1 ml of dilution was plated on each petri dish and pour plates were made. the 1/103 dilution had 250 colonies. the 1/104 dilution had 25 colonies. what was the cfu/ml of the original sample?

Answer 1

The CFU/ml of the original sample is 250,000.

Step-by-step explanation:

The CFU/ml of the original sample can be calculated by multiplying the number of colonies on each plate by the dilution factor.

In this case, the 1/10^3 dilution had 250 colonies and the 1/10^4 dilution had 25 colonies. The 1/10^3 dilution has a dilution factor of 10^3 and the 1/10^4 dilution has a dilution factor of 10^4.

Therefore, the CFU/ml of the original sample will be:

(250 colonies) x (10^3 dilution factor) = 250,000 CFU/ml

(25 colonies) x (10^4 dilution factor) = 250,000 CFU/ml

Hence, the CFU/ml of the original sample is 250,000.