Differential media or indicator media distinguish one microorganism type from another growing on the same media.
This type of media uses the biochemical characteristics of a microorganism growing in the presence of specific nutrients or indicators (such as neutral red, phenol red, eosin y, or methylene blue) added to the medium to visibly indicate the defining characteristics of a microorganism.
This type of media is used for the detection of microorganisms and by molecular biologists to detect recombinant strains of bacteria.
Examples of differential media include:
* eosin methylene blue (EMB), which is differential for lactose and sucrose fermentation
* MacConkey (MCK), which is differential for lactose fermentation
* mannitol salt agar (MSA), which is differential for mannitol fermentation
* X-gal plates, which are differential for lac operon mutants