Lauryl Tryptose (LST) Broth

Item No.  NCM0032A

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Lauryl Tryptose (LST) Broth is used for the detection of coliform bacteria in water and wastewater. Lauryl Tryptose Broth is not intended for use in the diagnosis of disease or other conditions in humans.

Lauryl Tryptose Broth is a selective medium for the detection of coliforms in water, dairy products and other foods. The American Public Health Authority (APHA) recommend Lauryl Tryptose Broth for the Most Probable Number Presumptive Test of coliforms in waters, effluent or sewage and as a confirmation test of lactose fermentation with gas production from milk samples and for the detection of coliforms in foods.

Lauryl Tryptose Broth is prepared according to the formulation of Mallmann and Darby. Mallmann and Darby showed that tryptose at a concentration of 2% increased the early logarithmic growth phase when compared to meat peptone. These researchers added phosphate buffers and sodium chloride, which improved gas production by "slow lactose fermenting" organisms. Sodium lauryl sulfate was incorporated as a selective agent for the inhibition of non-coliform organisms.

This medium can also be used with the addition of MUG (4- methylumbelliferyl-β-D-glucuronide) according to the ISO Standard 11866-2 to give enhanced detection of Escherichia coli.

Analyte Coliforms
Brand NEOGEN® Culture Media
Formula Liter
Tryptose 20.0 g/L
Lactose 5.0 g/L
Sodium Chloride 5.0 g/L
Dipotassium Phosphate 2.75 g/L
Potassium Dihydrogen Phosphate 2.75 g/L
Sodium Lauryl Sulfate 0.1 g/L
Grams per Litre 35.60
Litres per 500g 14.00
Mass 500 g
Package Dimensions 4.60 IN x 2.90 IN x 8.60 IN
Package Weight 1.35 LB
  1. Dissolve 35.6 grams of the medium in one liter of purified water.
  2. Mix thoroughly.
  3. Dispense into tubes or bottles containing inverted Durham tubes.
  4. Autoclave at 121ºC for 15 minutes.
Previous Item Number Product was previously known as Acumedia Product: 7323/7324 Lauryl Tryptose Broth; and LabM Product: LAB196 Tryptose Broth



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