Chromogenic Culture Media Technology

This technology is based on soluble colourless molecules (called chromogens), composed of a substrate (targeting a specific enzymatic activity) and a chromophore.
When the target organism’s enzyme cleaves the colourless chromogenic conjugate, the chromophore is released. In its unconjugated form, the chromophore exhibits its distinctive colour and, due to reduced solubility, forms a precipitate.

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Chromogenic agar Technology

 Source: Chromagar