Thursday 9 July 2015

Why only 10-100 cfu's or not more than 100 cfu's are required for growth promotion test of media?


During growth promotion test, We check whether media is capable of promoting growth of inoculated microorganisms or not.So, in GPT culture suspension of 10-100 cfu's or not more than 100 cfu's required because first thing is that we can easily count the number of recovered microorganisms on the media plate.


Growth Promotion test using not more than 100 cfu's
Another important thing is that we are challenging the media with the microorganisms and the microorganisms which we use for GPT should not be more than 5 passage removed form the original culture. So, we are working with the healthy microorganisms and these microorganisms should grow on the media which we are testing. This is like a challenge to use low number of microorganisms to check the growth promotion properties of the media. For this reason we use 10-100 cfu's or not more than 100 cfu's for growth promotion test.





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8 comments:

  1. Unknown14 October 2016 at 00:08

    In case sterilty testing we use pisitive culture of 10to 100cfu,but there was no need to count the colony,just see the turbidity and determind the growth..but my question is is this nessesery to use 10 to 100 cfu culture as a positive in sterility testig??

    ReplyDelete
    Replies
    1. Sandeep Dhiman24 January 2017 at 08:17

      In sterility testing you just check turbidity in the medium. The purpose of GPT is to challenge the media with low number of microorganisms.So 10-100 cfu's or not more than 100 cfu's used for GPT testing.
      Refer USP 39 chapter 61 and 62

      Delete
  2. Unknown22 February 2017 at 10:32

    Can we validate the load pattern of autoclave with 5000,ml glass
    bottles with 3000ml media.

    Thanks
    Dhanaji Gaikwad

    ReplyDelete
  3. Unknown22 February 2017 at 10:35

    Is it require to perform GPT TEST in duplicate , to reduce plate no.

    ReplyDelete
    Replies
    1. Unknown27 October 2017 at 11:31

      You do Gpt in duplicate,refer usp 40,chapter 61,& 62

      Delete
  4. Unknown22 February 2017 at 22:59

    Can we validate the load pattern of autoclave with 5000,ml glass
    bottles with 3000ml media.

    Thanks
    Dhanaji Gaikwad

    ReplyDelete
  5. Sandeep Dhiman2 November 2017 at 11:16

    dhanaji gaikwad, you can validate the load pattern rather is should be justified.

    ReplyDelete
  6. Hugo D. Melendez30 November 2017 at 06:56

    Is there a trick to growth promotion of Cetrimide Agar. Im having trouble growing pseudomonas with Bioball 550 on different manufacturers. Please help!

    ReplyDelete

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