MacConkey Agar without Crystal Violet

MacConkey Agar without Crystal Violet is used for the isolation and differentiation of Gram-negative enteric bacilli in a laboratory setting. MacConkey Agar without Crystal Violet is not intended for use in the diagnosis of disease or other conditions in humans.

MacConkey Agar is based on the bile salt-neutral red-lactose agar of MacConkey. The original MacConkey medium was used to differentiate strains of Salmonella typhosa from members of the coliform group. Formula modifications improved growth of Shigella and Salmonella strains. These modifications include the addition of 0.5% sodium chloride, decreased agar content, altered bile salts, and neutral red concentrations. The formula changes improved differential reactions between enteric pathogens and coliforms.

MacConkey Agar without Crystal Violet is a differential medium and less selective than MacConkey Agar. The lack of Crystal Violet permits growth of enterococci, staphylococci, and Mycobacterium spp.


Formula Liter
Enzymatic Digest of Gelatin 17 g
Enzymatic Digest of Casein 1.5 g
Enzymatic Digest of Animal Tissue 1.5 g
Lactose 10 g
Bile Salts Mixture 5 g
Sodium Chloride 5 g
Neutral Red 0.05 g
Agar 12 g

Final pH: 7.4 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.


  1. Suspend 52 g of the medium in one liter of purified water.
  2. Heat with frequent agitation and boil for one minute to completely dissolve the medium.
  3. Autoclave at 121°C for 15 minutes.

Order Details

Product # Product Description
7236A MacConkey Agar without Crystal Violet, 500 g
7236T MacConkey Agar without Crystal Violet, 5 kg