BAM Media M-197 LES Endo Agar (BD #273620)
February 2013
(Formula source: Standard Method for Examination of Water and Wastewater, 1998, 20th ed., p. 9-58 (3)
| Yeast extract | 1.2 g |
| Casitone or trypticase | 3.7 g |
| Thiopeptone or thiotone | 3.7 g |
| Tryptose | 7.5 g |
| Lactose | 9.4 g |
| Dipotassium hydrogen phosphate, K2HPO4 | 3.3 g |
| Potassium dihydrogen phosphate, KH2PO4 | 1.0 g |
| Sodium chloride, NaCl | 3.7 g |
| Sodium desoxycholate | 0.1 g |
| Sodium lauryl sulfate | 0.05 g |
| Sodium sulfite, Na2SO3 | 1.6 g |
| Basic fuchsin | 0.8 g |
| Agar | 15.0 g |
| Reagent grade water | 1 L |
Rehydrate product in 1 L water containing 20 mL 95% ethanol. Do not use denatured ethanol, which reduces background growth and coliform colony size. Bring to a near boil to dissolve agar, then promptly remove from heat and cool to 45 to 50 °C. Do not sterilize by autoclaving. Final pH 7.2 ± 0.2. Dispense in 5- to 7- mL quantities into lower section of 60-mm sterile petri dishes. If dishes of any other size are used, adjust quantity to give an equivalent depth of 4-5 mm. Do not expose poured plates to direct sunlight; refrigerate in the dark, preferably in sealed plastic bags to reduce moisture loss. Discard unused medium after 2 weeks or sooner if there is evidence of moisture loss, medium contamination or medium deterioration (darkening of the medium).