M-Endo Agar LES plate is used for enumerating coliforms in water by membrane filtration.
Endo Medium was first developed by Endo to differentiate between lactose-fermenters and non-fermenters. This medium employed sodium sulphite and basic fuchsin instead of bile salts to achieve inhibition of Gram-positive bacteria. M-Endo Agar, LES is a modification of the original medium and is formulated as per McCarthy et al., of Lawrence Experimental Station (LES) for testing coliforms in water using a two-step membrane filter procedure, wherein Lauryl Sulphate Broth is used as the primary enrichment medium. This medium is recommended by APHA for testing coliforms in drinking and in bottled water.
Composition*
| Ingredients | g/L |
| Casein Enzymic Hydrolysate | 3.7 |
| Peptic Digest of Animal Tissue | 3.7 |
| Tryptose | 7.5 |
| Yeast Extract | 1.2 |
| Lactose | 9.4 |
| Dipotassium Phosphate | 3.3 |
| Monopotassium Phosphate | 1.0 |
| Sodium Chloride | 3.7 |
| Sodium Deoxycholate | 0.1 |
| Sodium Lauryl Sulphate | 0.05 |
| Sodium Sulphite | 1.6 |
| Basic Fuchsin | 0.8 |
| Agar | 15.0 |
*Adjusted to suit performance parameters.
pH at 25°C ± 2°C: 7.2 ± 0.2
