If you obtain 35 colonies after spread plating 1 ml of a 1:500 dilution of lake...

Question

Question

If you obtain 35 colonies after spread plating 1 ml of a 1:500 dilution of lake water, what is the concentration of bacteria in the lake water?

Answer 1

Answer #1

Cfu/ml is calculated as = (No of colonies x Dilution factor) / Volume of the sample

No of Colonies=1

Dilution factor =1:500

Volume of the sample =1ml

(1 x 1:500) / 1

5 x 10² CFUs/ml

Answer 2

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