Letheen Broth, Modified (Modified Letheen Broth) is recommended for screening cosmetic products for microbial contamination. It is prepared as per FDA for screening cosmetic products for microbial contamination. The word Letheen represents a combination of lecithin and polysorbate (tween) 80. This methodology was adopted in 1965 by AOAC followed by FDA in 1978 including the same as a pre-enrichment step.