Habibeh Hajian Maleki MacConkey inhibits gram positive bacteria due to presence of bile salts and crystal violet while EMB agar inhibits gram positive bacteria in presence of methylene blue and eosin Y along with their specific differential properties in lactose and non-lactose fermentors.
The choice of which agar medium is more beneficial depends on factors such as the target organism, sensitivity of the medium, and the level of differentiation required. Each medium has its advantages and may be more suitable depending on the specific goals and requirements of the experiment or investigation.