Please someone help me solve this dilution problem. Thank you! You are doing a v

Question

Please someone help me solve this dilution problem. Thank you!

You are doing a viable cell count on a bacterial culture and you perform ten-fold serial dilutions as we did in class (Exercise 11). You spread 0.2 ml of each dilution on BHI plates and, after incubating at 370 overnight, obtain the results shown below. How many viable cells per milliliter are there in the undiluted bacterial culture? Show your work.

Dilution: 10-2, 10-3, 10-4, 10-5, 10-6, 10-7, 10-8

CFU: TNTC, TNTC, TNTC, 579, 61, 8, 1

Explanation / Answer

If we consider the dilution factor 10-5, the number of colony is 579 in 0.2 ml.

So, in 1 ml of culture the number of colony is 579 X 5 = 2895

That means 2.895 X 103.

So, the number of colony in undiluted sample is 2.895 X 103 X 105 = 2.895 X 108.

So, in undiluted bacterial culture, there will be 2.895 X 108 CFU/ml.

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