Lets say a stock culture of E coli was diluted by serial dil

Let\'s say a stock culture of E. coli was diluted by serial dilution as indicated below Then. 0.1 ml of suspension was removed from each tube and spread on a plate, and the colonies were counted, producing the following results What is the CFU/ml count for the undiluted stock?

Solution

From the results shown in this chart above, where the E. coli cells are spreaded from the serially diluted cultures would produce colonies. One form is shown where the numbers are numerous and subsequently less in the later dilutions. So we can easily say that CFU/ml count for the undiluted stock would be TNTC.

For the calculation of bacterial samples we always take either 10 power5 of 10 power 6 dlution, but here the CFU is TFTC. So the calculation for the stock per ml would be---with tube 3----153* 10^3 = 1.53 * 10^ 5 / 1530000 numbers.