Eosin Methylene Blue Agar (Powder)
Storage RT/4°C Shipping RT
Components shown as g/liter
Selective medium used to detect gram negative enteric bacteria. Contains both lactose and sucrose.
Eosin Methylene Blue Agar was first developed by Holt-Harris and Teague. This formula contains both lactose and sucrose with the two indicator dyes, eosin Y and methylene blue. Escherichia and Enterobacter species can be easily distinguished from other Gram negative enteric bacilli using this medium. EMB Agar contains two mildly selective dyes, eosin Y and methylene blue, which interact under strong acidic conditions to impart metallic sheen to Escherichia coli colonies. In addition, E coli produces dark blue-black colonies. Other coliforms produce mucoid, pinkish brown colonies. Non-lactose fermenting bacteria Salmonella and Shigella, produce translucent or colorless colonies. Acinetobacter, Aeromonas, Pseudomonas, Plesiomonas and Yersinia also grow on this medium. Gram-positive bacteria are inhibited by eosin Y. The slow lactose fermenters also ferment sucrose which reduces the incidence of false-positive interpretations.
Enterococcus faecalis ATCC 29212: Partial Inhibition, colorless
Escherichia coli ATCC 11775: Growth, blue-black colonies with dark center and green metallic sheen.
Salmonella typhimurium ATCC 14028: Growth, colorless colonies
Storage and Stability:
Store powdered media at RT. Opened bottles should be capped tightly and kept in a dark, low humidity environment. Prepared media should be kept at 4°C and used within a short period of time.
Directions per Liter Dissolve 36 grams in 800-900ml of ddH2O stirring gently with heating until completely solubilized. Add additional water to bring the solution to1L. Dispense into appropriate containers, loosen caps and autoclave for 15 minutes at 121ºC (15psi).
Storage and Stability: Store powdered media at RT. Opened bottles should be capped tightly and kept in a dark, low humidity environment. Prepared media should be kept refrigerated and used within a short period of time.
Appearance: Light reddish-purple, homogeneous, free flowing powder.
Solubility: Dark bluish to reddish-purple, clear to slightly turbid.
pH (25°C): 7.2±0.2
Microbiological Analysis: Enterococcus faecalis ATCC 29212
Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.