Fluid Thioglycollate Medium, 5 kg

Brewer (1) formulated Fluid Thioglycollate Medium for rapid cultivation of aerobes as well as anaerobes including microaerphiles by adding a reducing agent and small amount of agar. The British Pharmacopoeia (2) USP (3), EP (4) and AOAC (5) have recommended the media for sterility testing of antibiotics, biologicals and foods and for determining the phenol coefficient and sporicidal effect of disinfectants. However, it is intended for the examination of clear liquid or water-soluble materials. Glucose monohydrate, pancreatic digest of casein, yeast extract, L-cystine provide the growth factors necessary for bacterial multiplication. Sodium thioglycollate and L-cystine act as a reducing agent lowering the oxidation-reduction potential by removal of oxygen. This condition helps to prevent the accumulation of peroxides which is toxic in nature. The SH group of cystine also neutralizes the antibacterial effect of mercurial preservatives and other heavy metal compounds which exert a bacteriostatic effect in the materials under examination. Any increase in the oxygen content is indicated by a color change of redox indicator, resazurin to red (4,5, 6). The small amount of agar helps in maintaining low redox potential for stabilizing the medium (7). In sterility checking, it is recommended to dilute the sample containing preservatives, with this broth to reduce the toxicity and enhance the growth of contaminants, if any. Storage and Shelf-life: Store below 30°C in tightly closed container and the prepared medium at room temperature and away from light. Use before expiry date on the label. References: 1.Brewer, 1940, J. Am. Med. Assoc., 115:598. 2.British Pharmacopoeia, 2011, The Stationery office British Pharmacopoeia. 3.U.S. Pharmacopoeia, 2011, United States Pharmacopoeia Convention, Inc., Rockville, MD. 4.European Pharmacopoeia, 2011, European Department, for the Quality of Medicines. 5.Nungester, Hood and Warren, 1943, Proc. Soc. Exp. Biol. Med., 52:287. 6.Portwood, 1944, J. Bact., 48:255. 7.MacFaddin J.F., 1985, Media for Isolation-Cultivation-Identification-Maintenance of ,,Medical Bacteria, Vol.1, Williams and Wilkins, Baltimore.