m-ENDO agar LES

Appearance (clearness): clear to turbid
Appearance (color): red
pH-value (25 °C): 7.0 - 7.4
Growth (Escherichia coli ATCC 25922 (WDCM 00013)): good to very good
Growth (Enterobacter aerogenes ATCC 13048): good to very good
Growth (Proteus mirabilis ATCC 14273): good to very good
Growth (Staphylococcus aureus ATCC 25923 (WDCM 00034)): none
Growth (Enterococcus faecalis ATCC 19433 (WDCM 00009)): none to poor
Colony color (Escherichia coli ATCC 25922 (WDCM 00013)): red
Colony color (Enterobacter aerogenes ATCC 13048): red
Colony color (Proteus mirabilis ATCC 14273): reddish/red
Metallic luster (Escherichia coli ATCC 25922 (WDCM 00013)): +
Metallic luster (Enterobacter aerogenes ATCC 13048): +
Metallic luster (Proteus mirabilis ATCC 14273): -
Incubation: 24 hrs.; 35 °C; aerobic.

m-ENDO agar LES is suitable for the enumeration of coliforms in water using a two-step membrane filtration technique.

We offer two media types: the superior granulated GranuCult^® and the cost-efficient powdered NutriSelect^® culture media, depending on your needs. The designations basic, plus, or prime are added to indicate the quality control level, from basic quality control to standard QC plus to prime for full regulatory compliance.

m-ENDO Agar LES (Lawrence Experimental Station) is a medium recommended for the enumeration of coliforms in water used in the Standard Total Coliform Membrane Filter Procedure. The American Public Health Association (APHA) recommends m-Endo Agar in standard total coliform membrane filtration for testing potable water and wastewater. It follows the two-step membrane filter procedure using Lauryl Sulfate Broth as a preliminary enrichment, resulting in higher coliform counts. Peptones in the medium are a source of carbon, nitrogen, vitamins, and minerals. Yeast extract supplies B-complex vitamins, which stimulate bacterial growth. Lactose is a carbohydrate. Phosphates are buffering agents. Sodium chloride maintains the osmotic balance of the medium. Sodium desoxycholate and sodium lauryl sulfate are added to inhibit the growth of the accompanying flora. Pararosaniline (fuchsin) is an indicator. Sodium sulfite is added to decolorize the basic fuchsin solution. Agar is the solidifying agent. Lactose-positive colonies are colored red due to the liberation of fuchsin from the fuchsin-sulfite compound. E. coli colonies develop a metallic sheen due to the production of aldehydes with the rapid fermentation of lactose. Lactose-nonfermenting bacteria appear as clear, colorless colonies.

GRANUCULT is a registered trademark of Merck KGaA, Darmstadt, Germany

NutriSelect is a registered trademark of Merck KGaA, Darmstadt, Germany