4 replies to this topic

[miniaczka90]

Hey guys .

I was doing playing yesterday for coliform. I’ve got the results but first plate it is (1:10). My friend is saying that is TNTC. And I am saying it is okay coz this only has . Please see attached

[EagleEye]

Hi miniaczka90 and others,

Am I the only one who can't find an attachment here?

 

To conclude as TNTC, as you might know, it has to be in a form of a lawn- spread on plate and/or in a state one cannot count individual colonies. 

 

You could also go for the next dilution in this case to ensure this is not because of the abundance of the bacteria in the sample

Edited by EagleEye, 24 March 2019 - 04:41 AM.

[miniaczka90]

Hi

We did 3 dilutions .
The problem I have first one doesn’t show any colonies- only has . As far as I know at least I should see some colonies with gas.
I will attach picture one more time

Attached Files

•  F0E138EE-019F-48E2-8AC3-F963F6652D1C.jpeg   68.23KB   2 downloads

[EagleEye]

Hi miniaczka90,

The attachment is available now,

As I could see, it seems the first dilution marked as TNTC is appropriate given that colonies in the film (or in the picture?) appears uncountable and there is enormous gas formation also visible. If I were you, I would consider the second dilution in this case which is a typical countable film. If you have been confused with gas formation accountability, the second dilution film also shows gas surrounded (like a halo) colonies which you can see with a closer look (as per the picture).

 

As you might know, the general consideration in selection of countable plate is that plates with colonies 25 - 250. 

 

Have a great day!

[Charles.C]

Hey guys .

I was doing playing yesterday for coliform. I’ve got the results but first plate it is (1:10). My friend is saying that is TNTC. And I am saying it is okay coz this only has . Please see attached

 

It may relate to the product.

 

For example, for many raw products, need to use high dilutions for reason in post4.

 

Also, often, initial dilution plates suffer interference.

 

Also possible yr technique is questionable. Preferably use another more traditional method to compare results if not experienced, eg as in BAM. Or send to a lab.