MacConkey agar

Submitted by kdorfman on Thu, 01/17/2013 - 19:41

MacConkey Agar

  • Fisher 212122 2 kg (Difco)
  • Krackeler 10-211387 500g (via Sigma)

to distinguish Lac+ and Lac- bacterial strains.

50 g/L

To make Maconkey agar plates
at mm plate diameter
pour mL per plate
start with: mL water
add g Maconkey agar, heat to boiling, stir till dissolved
autoclave for: minutes

leave stir bar in

put bottles on stir plate near sterile hood until handle-able

If you accidentally buy HiMedia MacConkey agar w/o 0.15% Bile salts, Crystal Violet & NaCl:

Add per liter

  • 1.5 g bile salts (e.g., VWR BB0120-25G 470300-382 $9)
  • 0.001g crystal violet (.e.g., 0.1 mL of Fisher 3230-4 120 mL 1% $13.22)
  • 5 g NaCl