Harlequin® membrane Lactose Glucuronide Agar

Harlequin membrane Lactose Glucuronide Agar (mLGA) was developed as a modification of mLSB for the recovery and identification of coliforms and E. coli. The medium has been modified to identify E. coli based on β-glucuronidase enzyme activity. Sodium pyruvate was also included in this formula to aid the recovery of chlorine stressed organisms. This medium is recommended for the enumeration of coliform bacteria and E. coli by a single membrane filtration technique in The Microbiology of Drinking Water 2009 (previously Report 71).

Typical Formulation g/Liter
Peptone 40 g
Yeast extract 6 g
Lactose 30 g
Phenol red 0.2 g
Sodium Lauryl sulphate 1 g
Sodium pyruvate 0.5 g
X-Glucuronide (BCIG) 0.2 g
Agar 10 g
Grams per liter 88 g

Final pH: 7.4 ± 0.2


  1. Weigh 88 grams of powder and disperse in 1 liter of deionized water.
  2. Allow to soak for 10 minutes, swirl to mix.
  3. Autoclave for 10 minutes at 115°C.
  4. Cool to 47°C and mix well.
  5. Dispense into Petri dishes.