MacConkey plates

MacConkey Agar Fisher 212122 (Difco)

to distinguish Lac+ and Lac- bacterial strains.

50 g/L

Total plates needed =~625

in 2 L flasks

flasks Total vol (L) max # plates
1 1.75 70
2 3.5 140
3 5.25 210
4 7 280
5 8.75 350
6 10.5 420
7 12.25 490
8 14 540
  • 2-L flasks, each with:
    • 87.5 g MacConkey dry mix
    • 1.75 L distilled water
    • magnetic stir bar
  • Stir to mix.
  • Cover loosely with foil
  • Pack Pour-Boy tubing in foil to go in same cycle if it's not already sterile
  • Autoclave 55 min, liquid cycle
  • Cool till handle-able on stir plate
  • Dispense 25 mL per plate with Pour-Boy, stacking 10 tall.

in 4 L flasks

  • 4 L flasks, each with
    • 175 g MacConkey dry mix
    • 3.5 L distilled water
    • magnetic stir bar
  • Stir to mix.
  • Cover loosely with foil
  • Pack Pour-Boy tubing in foil to go in same cycle if it's not already sterile
  • Autoclave 75 min, liquid cycle
  • Cool till handle-able on stir plate
  • Dispense 25 mL per plate with Pour-Boy, stacking 10 tall
flasks total vol (L) max # plates
1 3.5 140
2 7 280
3 10.5 420
4 14 560