LETHEEN BROTH, AOAC *

Letheen Broth was developed by Quisno, Gibby and Foter by the addition of lecithin and Polysorbate 80 to FDA Broth. In the early 40s, Weber and Black recommended the use of lecithin and Polysorbate to neutralize the antimicrobial action of the quaternary ammonium compounds. Letheen Broth is recommended by AOAC to determine the phenol coefficient of cationic surfactants. Letheen Medium is also recommended for testing of cosmetics. The medium is also recommended by APHA for microbial testing of water.

for determination of bacterial activity of quaternary ammonium compounds using Escherichia coli or Staphylococcus aureus