Letheen Broth

Letheen Broth

SKU: KM0206 Category:

Letheen broth when prepared with polysorbate 80 is used for the testing of quaternary ammonium compounds for antimicrobial activity. Letheen broth is recommended by the Official Methods of Analysis of the Association of Official Analytical Chemists (AOAC). (1)
The enzymatic digest of animal tissue and beef extract act as carbon, nitrogen and vitamin sources in this medium. Sodium chloride maintains the osmotic balance of the medium. Lecithin inactivates quaternary ammonium compounds. Polysorbate 80 must be added to the medium prior to sterilisation. Polysorbate 80 neutralises phenols, formalin, hexachlorophene, and in combination with the lecithin, ethanol.

(1) Association of Official Analytical Chemists. 1995. Official methods of analysis, 16th ed. Association of Official Analytical Chemists, Washington, D.C

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 ATCC 8739 Growth
Staphylococcus aureus ATCC 6538 Growth

Recommended incubation: Aerobically at 37 ± 1°C for 18 – 24 hour


Enzymatic digest of animal tissue 10.0
Sodium chloride 5.0
Beef extract 5.0
Lecithin 0.7
Total 20.7


Suspend 20.7g of the medium in one litre of deionised / purified water. Add 5g of polysorbate 80 then allow the medium to soak whilst mixing for 10 minutes. Sterilise at 121°C for 15 minutes. Cool to 45-50°C and aseptically dispense into appropriate sterile containers.