EC Medium

EC Medium is used for the detection of coliform bacteria at 37°C and Escherichia coli at elevated temperatures (44.5 and 45.5°C) in a laboratory setting. EC Medium is not intended for use in the diagnosis of disease or other conditions in humans.

EC Medium was developed by Hajna and Perry in an effort to improve the methods for the detection of the coliform group and E. coli. This medium consists of a buffered lactose broth with the addition of 0.15% Bile Salts Mixture. Growth of spore-forming bacteria and fecal streptococci are inhibited by the bile salts, while growth of E. coli is enhanced by its presence. This medium can be used at 37°C for the detection of coliform organisms or at 44.5 or 45.5°C for the isolation of E. coli.

EC Medium is employed in elevated-temperature tests for distinguishing organisms of the total coliform group that also belong to the fecal coliform group. The fecal coliform test, using EC Medium, is applicable to investigations of drinking water, stream pollution, raw water sources, wastewater treatment systems, bathing waters, seawaters, and general water-quality monitoring. EC Medium is used in the MPN (Most Probable Number) test for fecal coliforms. EC Medium should not be used for the direct isolation of coliforms; prior enrichment in presumptive media is required for optimum recovery of fecal coliforms. EC Medium is used in methods for food and water testing.


Formula Liter
Tryptose 20 g
Lactose 5 g
Bile Salts Mixture 1.5 g
Dipotassium Phosphate 4 g
Monopotassium Phosphate 1.5 g
Sodium Chloride 5 g

Final pH: 6.9 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.


  1. Dissolve 37 g of the medium in one liter of purified water.
  2. Mix thoroughly.
  3. Distribute into tubes containing inverted fermentation Durham tubes.
  4. Autoclave at 121°C for 15 minutes.

Order Details

Product # Product Description
7206A EC Medium, 500 g
7206B EC Medium, 2 kg
7206T EC Medium, 5 kg