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Creating a protocol for testing microbiology media - (Apr/30/2015 )


My lab creates its own microbiology media. We want to be able to test each batch from lot to lot to make sure there's no variation between quality of the components prior to using it in research.


What is a good protocol to use for this? I think colony counts is what we will be using. Is there a certain protocol we should use in order to be able to start with the same amount of bacteria to inoculate with each time we test a new batch that we have made?


How do we go about storing the bacteria between tests? They would probably be stored for months at a time. Would we need to grow a culture of the bacteria up in growth medium prior to using it to test a new batch with it?


Thank you for your help!


For solid media, you could spread single colonies (well isolated) and measure colony diameter over time. For liquid media, you can do growth curves and establish doubling times. Both of these measure what you usually really care about.  Colony counts don't tell much except how many viable bacteria there are in a sample.


Rather than contrive a protocol - suggest you follow growth promotion protocol followed in the drug industry - USP <61>

-Phil Geis-