Calculate the expected average number of colonies per plate
Solution:
The original suspension = 200 /ml.
The volume of solution plated on 100 petri plates = 0.2 ml
Number of colonies per plate is counted by:
Add the values:
N = is the total colony number
= is the mean colony count of 5 sample plates
f = is the dilution factor
m = is the weight of the test portion in gram
x = is the dry matter content of the sample as a percentage
By inserting the values in the given formula, an average of 40 colonies per plate can be expected.