Thioglycollate Fluid Medium is used for detecting microorganisms in sterility tests, according to the formula specified in the European Pharmacopoeia, USP in the Paragraph 2.6.1 Sterility. Casein peptone provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Sodium thioglycollate neutralizes the bacteriostatic effect of the compounds used as preservatives in pharmaceutical preparations, especially injectables. Sodium thioglycollate and L-Cystine lower the oxidation-reduction potential by removing oxygen to maintain a low pH. Dextrose is the carbohydrate energy source and allows for a rapid and vigorous growth. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Resazurin is an oxidation indicator, turning from pink (aerobic) to colorless (anaerobic conditions). Bacteriological agar delays the dispersion of CO2 and diffusion of O2. With this medium, it is not necessary to use a cap of sterile paraffin oil or incubate in special containers for anaerobes. The anaerobic organisms develop at the bottom of the tube, the microaerophiles in the middle of the medium and the aerobes in the top oxidized layer. The European Pharmacopoeia recommends this medium in the paragraph 2.6.1: Microbiological examination of Sterile products for the sterility test for anaerobic bacteria. For products containing a mercurial preservative that cannot be tested by the membrane-filtration method, Thioglycollate Fluid Medium incubate at 20-25 °C may be used instead of Tripticasein Soy Broth (Cat. 1224). When the material in study contains other preservatives, use a sufficient amount of thioglycollate to dilute the inoculum beyond its bacteriostatic strength level.
Write Your Own Review