Lauryl Tryptose Broth / Lauryl Sulfate Broth

Lauryl Tryptose Broth and Lauryl Sulfate Broth, which are also known as Lauryl Sulfate Tryptose (LST) Broth, are used for the detection of coliform organisms in materials of sanitary importance. Coliforms are often used as indicators of fecal contamination in water and bacterial contamination in food products. Differences in naming conventions may reflect differences in the development and testing of media for industrial and clinical application.

Principles of BD Difco Lauryl Tryptose Broth / Lauryl Sulfate Broth Peptone provides essential growth substances, such as nitrogen and carbon compounds, sulfur and trace ingredients. The potassium phosphates provide buffering capacity. Sodium chloride maintains osmotic equilibrium. Lactose provides a source of fermentable carbohydrate for coliform organisms. The fermentation of lactose with gas formation is a presumptive test for coliforms. Sodium lauryl sulfate inhibits organisms other than coliforms.

Principles of Alpha Biosciences Lauryl Sulfate Broth Enzymatic Digest of Casein offers a source of nitrogen, vitamins, and minerals. Lactose is added to detect its fermentation by coliforms, while the Sodium Lauryl Sulfate acts as a selective agent against non-coliform organisms. Sodium Chloride is used to maintain the osmotic balance of the medium and the Potassium Phosphates act as buffering agents.