Bouillon au thioglycolate, 100 g

Glucose, peptone and yeast extract contained in the thioglycolate medium provide growth factors necessary for bacterial growth. The reducing agents sodium thioglycolate and L-cystine reduce the accumulation of peroxides, which are lethal to some microorganisms. Resazurin serves as a redox indicator; on oxidation it shows a pink colour, on reduction it is colourless.