acumedia* Letheen Agar with Tween

• Intended Use: Letheen Agar with Tween is used for the testing of quaternary ammonium compounds for antimicrobial activity.
• Product Summary and Explanation
In 1948, Weber and Black described the value of a highly nutritional solid medium containing neutralizing agents for quaternary ammonium compounds in sanitizers. The addition of Lecithin and Tween 80 (Polysorbate 80) to Tryptone Glucose Extract (TGE) Agar resulted in a medium that effectively neutralizes quaternary ammonium compounds while testing germicidal activity. Letheen Agar with Tween is a modification of TGE Agar, with the addition of Lecithin and Tween 80 (Polysorbate 80).
Letheen Agar with Tween is specified for use by the American Society for Testing Materials (ASTM) in Standard Test Method for Preservatives in Water-Containing Cosmetics. Total neutralization of disinfectants is critical. Disinfectant residues can result in a false negative (no-growth) test.
Letheen Agar with Tween has incorporated Tween 80 (Polysorbate 80) into the medium, this is the only difference from Letheen Agar Base.
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