EC Medium was developed by Hajna and perry to differentiate between fecal and non-fecal coliform bacteria. It is a buffered lactose broth which also contains bile salts which inhibits Gram positive cocci and spore formers. It was designed to improve the isolation and detection of E coli in contaminated water, milk and shellfish. APHA recommends that EC Broth be used for the determination of water pollution. Coliforms of fecal origin are detected by growth at 44.5°C. Fermentation of lactose is observed by gas bubbles present in an inverted fermentation tube. Selective broth medium used to detect the presence of coliform bacteria at 37.0°C and Escherichia coli at 44.5°C. (Alpha Biosciences # E05-100-2Kg)
Use: Selective broth medium used to detect the presence of coliform bacteria at 37.0°C and Escherichia coli at 44.5°C.
Description: EC Medium was developed by Hajna and perry to differentiate between fecal and non-fecal coliform bacteria. It is a buffered lactose broth which also contains bile salts which inhibits Gram positive cocci and spore formers. It was designed to improve the isolation and detection of E coli in contaminated water, milk and shellfish. APHA recommends that EC Broth be used for the determination of water pollution. Coliforms of fecal origin are detected by growth at 44.5°C. Fermentation of lactose is observed by gas bubbles present in an inverted fermentation tube.
Formula* per Liter:
- Casein Digest of Peptone .............. 20.0g
- Lactose ................................ 5.0g
- Sodium Chloride ................................ 5.0g
- Bile Salts Mixture .................1.5g
- Monopotassium Phosphate ..............1.5g
- Disodium Phosphate ...........4.0g
Final pH: 6.9± 0.2 at 25.0°C
* Grams per liter may be adj. or formula supplemented to obtain desired performance
Preparation: Mix 37 grams of the medium in one Liter of purified water until evenly dispersed. Heat with repeated stirring to dissolve completely. Prepare double strength broth for evaluating 10 mL samples. Distribute into test tubes containing inverted Durham tubes and autoclave at 121.0°C for 15 minutes.
Quality Control Specifications:
- The powder is homogeneous, free flowing and light beige.
- Visually the prepared broth is light to medium gold and clear.
- Expected cultural response after 18-24 hours at 44.5°C.
Organism                                                                            Result
Escherichia coli ATCC 25922Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Growth, Gas (+)
Enterobacter aerogenes ATCC 13048Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Inhibited, Gas (-)
Enterococcus faecalis ATCC 29212Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Inhibited, Gas (-)
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 light beige color.
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