MacConkey Agar is the earliest selective and differential medium for the cultivation of coliform organisms. It is used for the isolation and differentiation of non-fastidious gram-negative rods, particularly members of the family Enterobacteriaceae and the genus Pseudomonas.

MacConkey agar (MAC) is a bacterial culture medium named after bacteriologist Alfred T. MacConkey (1861-1931). MacConkey agar is a selective and differentiating agar that only grows gram-negative bacterial species; it can further differentiate the gram-negative organisms based on their lactose metabolism.

MacConkey agar is a selective and differential culture medium for bacteria. It is designed to selectively isolate Gram-negative and enteric (normally found in the intestinal tract) bacilli and differentiate them based on lactose fermentation. Lactose fermenters turn red or pink on McConkey agar, and nonfermenters do not change color.

MacConkey Agar is a solid, selective and differential culture media, specifically designed to promote the growth of gram-negative bacteria. Moreover, it enables the further distinction of Gram-negative organisms by assessing their ability to metabolize lactose : Lactose fermenters, colonies, turn red or pink on MacConkey agar

MacConkey Agar is a modified neutral red bile salt agar by Alfred Theodore MacConkey. It is one of the earliest methods used to cultivate and identify enteric organisms. MacConkey Agar is useful in isolating pathogens present in foods and coliforms in water samples.