EMB BROTH
CAT Nº: 1492
For the isolation and differentiation of gram negative enteric bacilli
FORMULA IN g/l
Peptic Digest of Animal Tissue
10.00
Dipotassium Phosphate
2.00
Lactose
5.00
Eosin Y
0.40
Sucrose
5.00
Methylene Blue
0.065
Final pH 7.2 ± 0.2 at 25ºC
PREPARATION
Suspend 22.5 grams of medium in one liter of distilled water. Mix well and dissolve by heating with frequent agitation.
Boil for one minute until complete dissolution. Distribute in appropriate containers and sterilize in autoclave at 121ºC for
15 minutes. The prepared medium should be stored at 2-8°C. The color is red with green tones. A Flocculent precipitate
may occur.
The dehydrated medium should be homogeneous, free flowing and red.pink in color. If there are any physical changes,
discard the medium.
USES
EMB BROTH is a differential medium used for the isolation of Enterobacteria.
The use of Eosin Y and Methylene Blue enable differentiation between lactose-fermenting and non-fermenting
organisms. It is widely used in medical bacteriology, in techniques recommended by APHA and for the detection and
enumeration of coliforms, contaminants of foods and drinking water. Peptone provide nitrogen, vitamins, minerals and
amino acids essential for growth. Sucrose is added to Lactose as a fermentable carbohydrate to detect coliforms that
ferment sucrose more readily than lactose. Eosin Y and Methylene blue dyes are both partial inhibitors of Gram-positive
bacteria and pH indicators. Due to the lactose and sucrose, the medium can be differential in primary culture:
Salmonellae and Shigellae which are lactose-negative can be differentiated from other lactose-negative and sucrosepositive organisms such as Proteus vulgaris, Citrobacter and Aeromonas. Dipotassium phosphate acts as a buffer system.
Incubate at 35 ± 2°C and observe at 18-24 hours.
MICROBIOLOGICAL TEST
The following results were obtained in the performance of the medium from type cultures after incubation at a
temperature of 35 ± 2ºC and observed after 18-24 hours
Microorganisms
Growth
Enterobacter aerogenes ATCC 13048
Proteus miriabilis ATCC 14273
Salmonella typhimurium ATCC 14028
Escherichia coli ATCC 25922
Staphylococcus aureus ATCC 25923
Good
Good
Good
Good
Inhibited
BIBLIOGRAPHY
American Public Heath Association. Diagnostic Procedures and Reagents. 2nd Ed. APHA, Inc. New York, 1950
1
LABORATORIOS CONDA, S.A.
www.condalab.com
A.P.H.A Examination of dairy products. 10th Ed. APHA, Inc. New York, 1953. Society of American Bacteriologists. Manual of
Microbiological Methods MacGraw-Hill New York, 1957.
STORAGE
25ºC
Once opened keep powdered medium closed to avoid hydration.
2ºC
2
LABORATORIOS CONDA, S.A.
www.condalab.com