Fluid Thioglycollate medium is supplied by HiMedia. It is a sterile ready prepared media containing 9ml of light straw-coloured clear solution in bottles. Fluid Thioglycollate medium is generally used for sterility testing of biologicals and for cultivation of anaerobes, aerobes and microaerophiles. It is advisable to store this ready prepared media between 2-8C. Composition (in gm/L) is as follows:

Tryptone (15.00)

Yeast extract (5.00)

Dextrose (Glucose) (5.50)

Sodium chloride (2.50)

L-Cystine (0.50)

Sodium thioglycollate (0.50)

Resazurin sodium (0.001)

Agar (0.75)

Brewer formulated Fluid Thioglycollate Medium for rapid cultivation of aerobes as well as anaerobes including microaerophiles by adding a reducing agent and small amount of agar. Dextrose, tryptone, yeast extract, L-cystine present in the medium, provide the growth factors necessary for bacterial multiplication. L-cystine and sodium thioglycollate permit the growth of Clostridium in this medium even under aerobic conditions. The relatively small amount of agar used in the medium favors the growth of aerobes as well as anaerobes in the medium, even if sodium thioglycollate is deleted from the medium. Sodium thioglycollate act as a reducing agent and neutralizes the toxic effects of mercurial preservatives and peroxides formed in the medium, thereby promoting anaerobiosis, and making the medium suitable to test materials containing heavy metals. Any increase in the oxygen content is indicated by a colour change of redox indicator, resazurin to red. The small amount of agar helps in maintaining low redox potential for stabilizing the medium.