Anonymous
Anonymous asked in Science & MathematicsBiology · 2 months ago

Help on this method of serial dilutions :(?

So I did I pilot run of my experiment to figure out how many dilutions id need to do.Theres too many colonies to count. I will attach a picture.

My lab teacher said that I should do my swabbing (I will be swabbing from a tile that has been sprayed with a solution) and then plate that. Wait for colonies to grow and then dilute it. I was very confused because I was going to do the swabs and instead of plating it dilute it then and there about 3 times and then plate it. Today was my trial run to see how many dilutions to do. As you can see theres a lot of colonies meaning ill need to dilute mayeb 3/4 times 

I asked how how am I going to dilute the bacteria thats already on the plate and she said to get an inoculating loop which holds 10micro litres(Idk of what please clarify ?) and put it into 10ml of water and then plate that. But im still confused how Im going to get bacteria off the plate? do I swab the inoculating loop onto the plate and then put it into the water?

She then said to see how many colonies grow and then do the same again. I am very confusd on her method can someone elaborate and give step by step. I have already seen that theres a lot of colonies so Ill need to dilute it more than once. How do I do that with her method of the inocualting loop. I said that once I do the first dilution ill need to transfer 10mls into another test tube and she just said no I will repeat what she told me to do again??

Please keep it simple thanks

Update:

Original plan is what I want to stick to. It was to swab tile and then dilute. Take 1ml out put into another test tube with 9ml of water and keep diluting 3/4 times and then plate.

Isnt this method better?

Attachment image

1 Answer

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  • Anonymous
    2 months ago

    Just lick it and see what happens. In class i once poured my "load" into the beaker and the teacher heated it up so the school evacuated (mine smells like a dead rodent)

    Source(s): Wolrd Health Organisation
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