Lauryl Tryptose Broth

Lauryl tryptose broth (LSB) is a selective growth medium for coliforms. The American Public Health Association (APHA) recommends that lauryl tryptose broth should be used for the Mean Probable Number Presumptive Test of coliforms in waters, effluent or sewage as a confirmatory test of lactose fermentation with gas production for milk samples.Sodium lauryl sulfate inhibits organism other than coliforms.

Formula in grams/litre (g/l)

Tryptose: 20.0,
Lactose : 5.0,
Sodium chloride : 5.0,
Dipotassium phosphate : 2.75,
Potassium dihydrogen phosphate : 2.75,
Sodium dodecyl sulfate : 0.1
pH 6.8 ± 0.2