if 005mL of a 106 dilution yielded an average of 317 colonie

if 0.05mL of a 10^-6 dilution yielded an average of 317 colonies/plate, calculate the number of cells per mL of the original culuture. Show all calculations

Solution

Answer:

Number of bacteria per mL = Number of bacteria in the dilution plate / dilution

Here, 0.05 mL of the culture yields 317 colonies in the plate.

So, 1 mL of the culture yields 317/0.05 colonies.

Therefore, number of bacteria per mL of the original culture = 317/(10^-6 * 0.05)

= (317/0.05) * 10⁶

= 6340 * 10⁶ bacteria