Total Colony Counts - What is the definition of Total Colony Counts, pls? (Oct/01/2008 )
Hi all,
I have come across a lot of specific terms like total colony count, total viable colony count, total plate count and so on. Actually, I wish to know wat are the differences between all of this. Are they actually represent the same meaning, which is regarding the number of bacteria present? And can somebody provides me information on which countries are including this specification in their drinking or bottled water guidelines and they are setting what value of detection limit on this? I am very grateful if any gentlemen o ladies can enlighten me on this.
I have come across a lot of specific terms like total colony count, total viable colony count, total plate count and so on. Actually, I wish to know wat are the differences between all of this. Are they actually represent the same meaning, which is regarding the number of bacteria present? And can somebody provides me information on which countries are including this specification in their drinking or bottled water guidelines and they are setting what value of detection limit on this? I am very grateful if any gentlemen o ladies can enlighten me on this.
I am not sure where you came across these terms, but I think those mean the same: the "CFU" (means colony forming units) which can be visualised by plating your sample on media, incubate it and count them. The "viable" in the second expression highlights a problem when working with microbes: not all microbes present are "alive" (i.e. when you filtrate the sample, stain it and count the single microbes with a microscope you will see more than you will be able to culture) or viable on cultute media;
As far as I remember it is recommended in different standards to state the numbers in the above mentioned "CFU" per g or mL to get comparable data in your different tests.
For the guidelines: look at EurLex for Europe; and maybe you can find something at the Codex alimentarius.....
Actually people working in microbiology know it means mesophilic aerobic bacterial colony count.
We can only culture a microbe at/on:
1.one temperature at a time
2.either aerobic or anaerobic (or less aerobic, or even with added carbon dioxide or else) at a time
3. one medium at a time
Therefore different terms are used in different books, test standards, etc. Some examples are:
1. Total aerobic microbial count (United States Pharmacopeia)
2. Total viable aerobic count (British Pharmacopoeia)
3. Aerobic plate count (FDA, Bacteriological Analytical Manual)
All incubation temperatures are within 30~37 degree Celsius.
All under aerobic condition.
All use media with similar constituents.