M-Endo Agar LES is supplied by Micromaster. It is available in the form of a light pink to purple homogeneous free flowing powder which has a pH in the range of 7.0 to 7.4. It is advisable to store this product below 30C.

Quantity provided: 100 g/pack

M-Endo Agar LES is used for enumeration of coliforms in water using a two-step membrane filter method. It is possible to remove bacteria from fluids by passing them through filters with such small pore size that bacteria are arrested. 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. Presumptive coliform bacteria will form red colonies with metallic sheen after an incubation at 35-37C for 24 hours. Casein enzymic hydrolysate, tryptose, peptic digest of animal tissue and yeast extract provide essential nutrients especially nitrogenous for the coliforms. Lactose is the fermentable carbohydrate. Sodium sulphite, sodium deoxycholate and basic fuchsin inhibit the growth of gram-positive organisms. Phosphates buffer the medium. Coliforms ferment lactose and the resulting acetaldehyde reacts with sodium sulphite and basic fuchsin to form red colonies and similar colouration of the medium. Lactose non-fermenters form colourless colonies.