(AB) m-Endo Agar, LES, 500 grams

McCarthy, Delaney and Grasso formulated Endo Agar LES (Lawrence Experimental Station) for testing water for coliform bacteria by a two-step filter procedure using Lauryl Tryptose Broth as a preliminary enrichment. They recovered higher numbers of coliforms by this method compared with the one step technique using m Endo Broth. The American Public Health Association specifies using m Endo Agar, LES in the standard total coliform membrane filtration procedure for testing drinking water and bottled water. It is also specified for use in the completed phase of the standard total coliform fermentation technique. The coliform bacteria are bacteria that produce a red colony with a metallic (golden) sheen within 24 hours incubation at 35.0°C on an Endo-type medium. The U.S. Environmental Protection Agency specifies using m Endo Agar, LES in the total coliform methods for testing water using single-step, two-step and delayed incubation membrane filtration methods. m Endo Agar, LES is used for enumerating coliforms in water by membrane filtration. (Alpha Biosciences # M13-124-500gm)

Use: m Endo Agar, LES is used for enumerating coliforms in water by membrane filtration.

Description: McCarthy, Delaney and Grasso formulated Endo Agar LES (Lawrence Experimental Station) for testing water for coliform bacteria by a two-step filter procedure using Lauryl Tryptose Broth as a preliminary enrichment. They recovered higher numbers of coliforms by this method compared with the one step technique using m Endo Broth. The American Public Health Association specifies using m Endo Agar, LES in the standard total coliform membrane filtration procedure for testing drinking water and bottled water. It is also specified for use in the completed phase of the standard total coliform fermentation technique. The coliform bacteria are bacteria that produce a red colony with a metallic (golden) sheen within 24 hours incubation at 35.0°C on an Endo-type medium. The U.S. Environmental Protection Agency specifies using m Endo Agar, LES in the total coliform methods for testing water using single-step, two-step and delayed incubation membrane filtration methods.

Formula* per Liter:

• Casitone ............................................ 3.7g
• Yeast Extract ............................. 1.2g
• Sodium Chloride ............................... 3.7g
• Thiopeptone .............................. 3.7g
• Tryptose ............................................. 7.5g
• Lactose ...................................... 9.4g
• Dipotassium Phosphate .................. 3.3g
• Sodium Deoxycholate .............. 0.1g
• Monopotassium Phosphate ............ 1.0g
• Sodium Sulfite .......................... 1.6g
• Sodium Lauryl Sulfate .................... 0.05g
• Basic Fuchsin ........................... 0.8g
• Agar ..........................................15.0g

Final pH: 7.2 ± 0.2 at 25.0°C

* Grams per liter may be adj. or formula supplemented to obtain desired performance

Preparation: Mix 51.0 grams of the medium in one Liter of purified water containing 20 ml ethanol until evenly dispersed. Heat with repeated stirring and boil for one minute to dissolve completely. DO NOT AUTOCLAVE.

Quality Control Specifications:

1. The powder is homogeneous, free flowing and purple.
2. Visually the prepared medium is rose colored, slightly opalescent with a precipitate.
3. Expected cultural response after 20-24 hours at 35.0°C.

Organism                                                                          Result

Escherichia coli ATCC 25922                Growth, Red colonies with green metallic sheen.

Salmonella typhimurium ATCC 14028                    Growth, pink colonies

Staphylococcus aureus ATCC 25923                         Growth Inhibited

Storage: Store the sealed bottle containing the dehydrated medium at 2 to 30.0°C. Once opened and recapped, place the container in a low humidity environment at the same storage temperature. Protect it from moisture and light. The dehydrated medium should be discarded if it is not free flowing or if the color has changed from the original purple color.