Fluid Thioglycollate Medium(USP)

Fluid Thioglycollate Medium(USP)is used for the sterility testing of biologics and for

the cultivation of anaerobes, aerobes and microaerophiles.

Approximate Formula:

Ingredients	gm/liter
Pancreatic Digest of Casein	15.0
Yeast Extract	5.0
Dextrose	5.0
Sodium Thioglycolate	0.5
L-Cystine	0.5
Sodium Chloride	2.5
Resazurin	0.001
Agar	0.75
Final pH 7.1±0.2 at 25??
*Adjusted and/or supplemented as required to meet performance criteria.

Directions:

Suspend 29.25g of the medium in one liter of distilled water or deionized water. Mix well and heat with frequent agitation. Dispense into triangle flasks. Sterilize in an autoclave at 121??(15 lbs.) for 15 minutes.

Principle and Interpretation:

Dextrose, pancreatic digest of casein, L-cystine and yeast extract provide the growth factors necessary for bacterial replication. Sodium thioglycollate is a reducing agent that prevents the accumulation of peroxides which are lethal to some microorganisms. The L-cystine is also a reducing agent. Resazurin is an oxidation-reduction indicator, being pink when oxidized and colorless when reduced. The small amount of agar assists in the maintenance of a low redox potential by stabilizing the medium against convection currents, thereby maintaining anaerobiosis in the lower depths of the medium.

Appearance:

Dehydrated medium is a free-flowing yellowish powder.

The prepared medium is a kind of yellowish fluid.

Precautions:

This medium is for laboratory use only.

Dried medium which is past shelf life, caking or color variation cannot be used.

Storage conditions and Shelf life:

Fluid Thioglycollate Medium must be stored tightly capped in the original container at 5-30°C. The dehydrated medium has a shelf life of 3 years from date of manufacturing. Prepared medium may be stored, out of direct light at 2-8°C.

Quality control:

Inoculate and incubate at 30-35?? for 24-72 hours.

Reference:

1. GB4789.28-2013 People's Republic of China food safety national standard food microbiology test medium and reagent quality requirements.

2.Linden. 1941. Fluid thioglycollate medium for the sterility test. National Institutes of Health, Bethesda, Md.