Eosin methylene blue agar (EMB) is a selective and differential medium used to isolate fecal coliforms. Eosin Y and methylene blue are pH indicator dyes which combine to form a dark purple precipitate at low pH; they also serve to inhibit the growth of most Gram positive organisms
Methylene blue: 0.065 g
Agar: 13.5 g
Eosin Y: 0.4 g
Lactose: 5 g