MacCONKEY AGAR W/ CV W/O NaCl

The MacConkey media are well known and popular enrichment system for coliform bacteria. MacConkey Agar is the earliest selective and differential medium for cultivation of enteric microorganisms from a variety of clinical specimens. Original formulation of MacConkey included ox bile as inhibitor of gram-positive bacteria and litmus as the indicator of the acid production from lactose. Later litmus was substituted by phenol red indicator to make interpretation easier and more precise. The most significant modification to the original formulation is the substitution of ox bile by purified bile salts that improve the selectivity and avoid the inherent turbidity which is due to the fat material of the bile. Another modification was the inclusion of supplementary inhibitors such as crystal violet and pH indicator neutral red.
MacConkey Agar has been recommended for use in microbiological examination of foodstuffs and for direct plating of water samples for coliform counts. These media are also accepted by the Standard Methods for the Examination of Milk and Dairy Products.

recommended for the selection and recovery of the Enterobacteriaceae and related enteric gram-negative bacilli