Counting the number of bacteria
Posted: Tue Jan 31, 2017 5:28 am
Hello everyone. My question is: How can I count the number of a bacteria taken from a solid sample?
I know everything about pour plate method when I already have a solution of bacteria, which firstly needs to be diluted and then transferred to a petri dish. What confuses me is how to do that with a solid sample.
I understand that the procedure is pretty much the same, only this time, I need to make the solution first. The question is how to do that the right way?
If I dissolve the simple in some amount of water, isn't that dilution already? And in which amount of water should I dissolve it? How would I count the number of bacteria later, if I don't know how much of the original sample is there? For example, If I am using the loop to take the sample from the petri dish and transfer it to the water, I don't know the exact amount that is in the loop, so I can't count the concentration that I am starting with.
I hope you understand what I am asking.
Thank you for your answers!
I know everything about pour plate method when I already have a solution of bacteria, which firstly needs to be diluted and then transferred to a petri dish. What confuses me is how to do that with a solid sample.
I understand that the procedure is pretty much the same, only this time, I need to make the solution first. The question is how to do that the right way?
If I dissolve the simple in some amount of water, isn't that dilution already? And in which amount of water should I dissolve it? How would I count the number of bacteria later, if I don't know how much of the original sample is there? For example, If I am using the loop to take the sample from the petri dish and transfer it to the water, I don't know the exact amount that is in the loop, so I can't count the concentration that I am starting with.
I hope you understand what I am asking.
Thank you for your answers!