Media used for coliform enumeration often changes color based on the enzymes present in the microbes. This type of medium is termed?

The correct designation for media that changes color based on the enzymes present in the microbes is termed differential medium. Differential media are specifically designed to allow for the differentiation among different species of microorganisms based on their biochemical characteristics. This is accomplished through the incorporation of substances that will react with by-products of microbial metabolism, resulting in a change of color or appearance.

In the case of coliform enumeration, differential media may contain indicators that change color when coliforms ferment lactose, producing acid and possibly gas as a by-product. This visual change helps microbiologists identify and confirm the presence of these bacteria in a sample.

Selective media, on the other hand, are formulated to inhibit the growth of some microorganisms while allowing others to grow, which is not the case in this scenario. Enrichment media provide specific nutrients that favor the growth of a particular group of microbes, often leading to an increase in their numbers but not necessarily indicating their presence through a color change. Complex media contain a variety of nutrients but do not specifically alter color based on microbial activity, unlike differential media, which are tailored for such detection based on enzymatic activity.