Product number: 7378

MacConkey Agar without Crystal Violet & Salt is used for the isolation and differentiation of Gram-negative enteric bacilli from specimens containing swarming strains of Proteus spp. in a laboratory setting. MacConkey Agar without Crystal Violet & Salt 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 modifications improved differential reactions between enteric pathogens and coliforms.

MacConkey Agar without Crystal Violet & Salt is a differential medium that restricts swarming of Proteus spp., aiding in the detection and isolation of enteric microorganisms. Sodium Chloride is deleted from the medium to provide an electrolyte deficient medium preventing Proteus spp. from spreading. In addition, this medium does not contain crystal violet allowing Staphylococcus, Enterococcus, and Mycobacterium spp. to grow.


Formula Liter
Enzymatic Digest of Casein 18.5 g
Enzymatic Digest of Animal Tissue 1.5 g
Lactose 10 g
Bile Salts Mixture 5 g
Neutral Red 0.04 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 47 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
7378A MacConkey Agar without Crystal Violet & Salt, 500 g
7378T MacConkey Agar without Crystal Violet & Salt, 5 kg

Reference Material

7378 - MacConkey Agar without CV & Salt, Product Information Sheet [English]
7378 - MacConkey Agar without CV & Salt, Safety Data Sheet [Danish] [Dutch] [English] [EU English] [Finnish] [French] [German] [Italian] [Spanish, Mexico] [Swedish]

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