Pink or Purple Growth Color in EMB Agar: Lactose Fermenters

What kind of fermenters produce pink or purple growth color in EMB agar?

A. Lactose fermenters

Answer:

Lactose fermenters produce pink or purple growth color in EMB agar.

Lactose fermenters play a significant role in producing the pink or purple growth color in EMB agar. Eosin Methylene Blue (EMB) agar is a specialized medium used for the selective isolation and differentiation of organisms such as Escherichia coli and other Gram-negative enteric bacteria.

When lactose fermenters are present on EMB agar, they utilize lactose as a carbon source and produce acid and gas as byproducts of fermentation. This acid production leads to a decrease in pH, resulting in the development of the pink or purple coloration on the agar. The differentiation of lactose fermenters from other non-fermenting bacteria is crucial for microbiological identification purposes.

Understanding the characteristics and behaviors of lactose fermenters in EMB agar is essential for microbiologists in identifying and distinguishing between different bacterial species. The ability to recognize specific growth patterns and color changes aids in the accurate classification of organisms for further analysis and research.