This Biplate is a combination of Nutrient Agar + MacConkey Agar W/0.15% Bile salts, CV and NaCl and is recommended for selective isolation and differentiation of coliform and other enteric pathogens. MacConkey Agar is based on lactose fermentation . Neutral red is the indicator for detecting lactose fermentation. Bile salts and crystal violet inhibits gram positive organisms. Nutrient agar is non selective medium and allows the growth of most of the organisms.