What is the function of indicators in microbiological media?

Indicators in microbiological media serve the critical function of detecting changes in the media, particularly changes in pH or the presence of specific metabolic activities by microorganisms. These indicators are often added to the media to visually signal whether a particular biochemical reaction has occurred. For example, a pH indicator might change color in response to acid production by fermenting bacteria, making it possible to identify or differentiate species based on their metabolic capabilities.

The presence of an indicator allows scientists and microbiologists to interpret the results of their cultures more easily. Without the use of indicators, it would be much harder to determine the metabolic activity of the microorganisms grown in the media, which is essential for classification, identification, and understanding of the microorganisms’ ecological roles. This makes the use of indicators an invaluable tool in microbiological studies.