Fluid Thioglycollate Medium (FTM) plates is used for sterility testing of biologics and for the cultivation of anaerobes, aerobes and microaerophiles.

Sodium thioglycollate is a reducing agent that prevents the accumulation of peroxides which are lethal to some microorganisms. Cystine is also a reducing agent, containing sulfhydryl groups which inactivate heavy metal compounds to maintain a low redox potential, thus supporting the growth of anaerobic organisms. Resazurin is an oxyidation-reduction indicator which turns pink when oxidized and colorless when reduced. The small amount of agar assists in maintenance of low redox potential which helps support the growth of anaerobic organisms.