Thioglycollate Broth U.S.P. | DM221D

Thioglycollate Broth U.S.P. | DM221D

For sterility testing as recommended by the United States Pharmacopoeia.

Brewer1 described the use of thioglycollate to create conditions for the growth of clostridia without anaerobic jars. The original formulation of the broth used meat products and was shown to be inadequate for certain clostridia by McClung2.
Subsequent work by Brewer3 and Vera4 was utilised in the formulation of a more nutritious medium described by Pittman5. This medium was adopted by the National Institute of Health for sterility testing and is described in the U.S. Pharmacopoeia (1970).6 Thioglycollate reduces the Eh potential of the broth and allows the growth of anaerobes and aerobes without the use of anaerobic apparatus. Resazurin is used to indicate the Eh potential of the medium in preference to methylene blue, as the latter is more inhibitory. Agar is present to minimise convection and absorption of oxygen. Thioglycollate also neutralises mercurial preservatives in test materials as shown by Nungester et al.7

Technical Formula

Directions

1. Suspend 29.8g of powder in 1 litre or the contents of the sachet in the stated volume of distilled or deionised water.
2. Boil at 100ºC to dissolve the agar and distribute into test tubes.
3. Autoclave at 121ºC (15 p.s.i.) for 15 minutes.
4. Reboil before use if more than one third of the column turns blue on storage. Do not reheat more than once.