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MacConkey Agar with Sorbitol

MacConkey Agar with Sorbitol is used for the isolation of pathogenic Escherichia coli in a laboratory setting. MacConkey Agar with Sorbitol is not intended for use in the diagnosis of disease or other conditions in humans.

MacConkey Agar with Sorbitol is based on the formula by Rappaport and Henig. Originally developed for isolating enteropathogenic (EPEC) serotypes, O11 and O55, this medium is recommended for the isolation and differentiation of enterohemorrhagic E. coli O157:H7. Serotype O157 has been implicated in serious foodborne diseases.

MacConkey Agar with Sorbitol contains sorbitol instead of lactose for differentiating enteropathogenic E. coli serotypes; these strains are typically sorbitol negative. MacConkey Agar with Sorbitol is recommended for food testing.

 

Formula Liter
Enzymatic Digest of Gelatin 17 g
Enzymatic Digest of Casein 1.5 g
Enzymatic Digest of Animal Tissue 1.5 g
Sorbitol 10 g
Bile Salts Mixture 1.5 g
Sodium Chloride 5 g
Neutral Red 0.03 g
Crystal Violet 0.001 g
Agar 13.5 g

Final pH: 7.1 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.

Directions

  1. Suspend 50 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.
  4. Cool to 45 – 50°C and dispense into sterile Petri dishes.

Order Details

Product # Product Description
7320A MacConkey Agar with Sorbitol, 500 g
7320T MacConkey Agar with Sorbitol, 5 kg