m-Endo Agar

m-Endo Agar is used for the enumeration of coliforms in water by the membrane filtration method in a laboratory setting. m-Endo Agar is not intended for use in the diagnosis of disease or other conditions in humans.

The coliform group, especially Escherichia coli, are used as indicators of fecal pollution in water, for assessing the effectiveness of water treatment and disinfection, and for monitoring water quality. m-Endo Agar is prepared according to the formula of McCarthy, Delaney, and Grasso, and used in testing water for coliforms by a two-step membrane filtration procedure. Lauryl Tryptose Broth is used as the preliminary enrichment, resulting in higher coliform counts.

The American Public Health Association (APHA) recommends m-Endo Agar in standard total coliform membrane filtration procedure for testing water, wastewater, and foods. The US EPA specifies using m-Endo Agar in the total coliform methods for testing water. m-Endo Agar is also known as LES (Lawrence Experimental Station) Endo Agar.


Formula Liter
Lactose 9.4 g
Tryptose 7.5 g
Enzymatic Digest of Casein 3.7 g
Enzymatic Digest of Animal Tissue 3.7 g
Sodium Chloride 3.7 g
Potassium Phosphate, dibasic 3.3 g
Sodium Sulfite 1.6 g
Yeast Extract 1.2 g
Potassium Phosphate, monobasic 1 g
Basic Fuchsin 0.8 g
Sodium Deoxycholate 0.1 g
Sodium Lauryl Sulfate 0.05 g
Agar 15 g

Final pH: 7.2 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.


Non-denatured Ethanol, 20 mL


  1. Suspend 51 g of the medium in 1 liter of purified water containing 20 mL of non-denatured Ethanol.
  2. Heat with frequent agitation and boil to completely dissolve the medium.
  3. Avoid overheating. DO NOT AUTOCLAVE.

Order Details

Product # Product Description
7724A m-Endo Agar, 500 g
7724T m-Endo Agar, 5 kg