Other common names

Fluid Thioglycollate Medium doesn’t tend to have other name variants. It is also universally known by its abbreviated name FTM. 


Primary Use

Fluid Thioglycollate Medium (FTM) is used for the isolation and cultivation of aerobic and anaerobic organisms and is widely used in sterility testing applications. The addition of a small quantity of agar helps to retain the anaerobic conditions within the medium. 

 

 

Technical characteristics


The medium’s complex formulation includes a small amount of agar and resazurin. The agar controls the ingress of oxygen within the medium to maintain anaerobiosis in the lower part of the medium. The resazurin is an indicator dye which in the presence of oxygen turns pink.   

Typical formulation: g/ltr
Yeast extract 5.0
Tryptone 15.0
Glucose 5.5
Sodium thioglycollate 0.5
Sodium chloride 2.5
L-cystine 0.5
Resazurin 0.001
Agar 0.75

pH 7.1 ±0.2

Applications

 

The main application for FTM is in sterility testing of products within pharma manufacturing. The harmonised pharmacopoeia medium is typically used alongside Tryptic Soy Broth (TSB). 

As with most liquid medium, growth of microorganisms shows as turbidity in the otherwise clear liquid. 

Appearance


The prepared media is clear pale straw / yellowish liquid which can have a slightly opaque appearance in large volumes due to the small amount of agar in the formulation. 

The medium can have an upper layer pink in colour. This is caused by oxidation within the medium, if the medium presents a pink layer less than a third of the overall volume, oxygen can be reduced by heating the medium once in a water bath.

 

Organisms & morphology


Fluid Thioglycollate Medium will support growth of a wide range of aerobic and anaerobic bacteria if incubated under the right conditions.  A typical set of control organisms are:

Organism

Reaction

Staphylococcus aureus

Turbid/ visible  growth  

Staphylococcus epidermidis

Turbid/ visible  growth  

Escherichia coli

Turbid/ visible  growth  

Bacillus subtilis

Turbid/ visible  growth  

Pseudomonas aeruginosa

Turbid/ visible  growth  

Candida albicans

Turbid/ visible  growth  

Clostridium sporogenes

Turbid/ visible  growth  


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Typical incubation parameters

FTM medium is incubated at 30-35°C  for the recovery of bacterial cultures. Due to the design of the media there is no requirement to incubate anaerobically for the recovery of anaerobic organisms.  

Regulatory references

FTM is a Harmonised Pharmacopoeia medium and as such is mentioned in the BP/EP/JP, as well as the US Pharmacopoeia. 

EP Chapter Ref 2.6.1 Sterility testing

Recommended Culture Media

Property

Micro-organisms

Incubation Time & Temp

Fluid Thioglycollate Medium

Growth promotion

Clostridium sporogenes 

Pseudomonas aeruginosa 

Staphylococcus aureus 

30-35ºC for < 3 days


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Related reading:

 

The Pharmaceutical and Cleanroom Industry's Pocket Guide to Prepared Media

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