Lauryl Tryptose Agar

//Lauryl Tryptose Agar

Lauryl Tryptose Agar

SKU: KM0117 Category:

Lauryl Tryptose Broth is a selective medium for the detection of coliforms in water and wastewater.
This formulation is based on the Mallmann and Darby formulation. (1)
The tryptone provides the required carbon, nitrogen and vitamins in this medium.
Lactose is a fermentable carbohydrate.
The sodium chloride maintains the osmotic balance whilst the dipotassium hydrogen phosphate and potassium hydrogen phosphate act as buffers.
Sodium lauryl sulphate is a selective again used to inhibit non-coliforms.

(1) Mallmann, W. L. and Darby, C. W. 1941. Uses of a lauryl sulphate tryptose broth for the detection of coliform organisms. Am J. Public Health. 31:127

Additional Information

Shelf Life (days)

Dehydrated Medium Appearance

Dehydrated Medium Colour

Dehydrated PH

Prepared Medium Appearance

Prepared Medium Colour

Prepared PH



Product Description

Organisms Ref. No Result
Escherichia coli NCTC 12241 Growth with gas production
Enterococcus faecalis NCTC 12697 Inhibited


Recommended incubation: Aerobically at 37 ± 1°C for 18 -48 hours.


Tryptone 20.0
Lactose 5.0
Sodium chloride 5.0
Dipotassium hydrogen phosphate 2.75
Potassium dihydrogen phosphate 2.75
Sodium lauryl sulphate 0.1
Total 35.6
*Adjusted/supplemented as required to meet performance requirements


Suspend 35.6g of the medium in one litre of deionised / purified water.
Allow the medium to soak whilst mixing for 10 minutes.
Dispense into appropriate containers with fermentation tubes (Durham).
Sterilise at 121°C for 15 minutes.