Other common names

TSB can be referred to using other names by the various manufacturers of dehydrated culture media, these include Casein Soya Bean Digest Broth, Soybean Casein Digest Broth, CASO Broth, Trypticase® Soy Broth and Tryptone Soya Broth


Primary Use

Tryptic Soy Broth is a general purpose highly nutritious liquid medium for the cultivation of a wide variety of fastidious and non-fastidious organisms, including both aerobes and anaerobes, although the latter may require anaerobic conditions. 

 

 

Technical characteristics

The medium’s simple formulation consists of two types of peptone and sodium chloride.

 
Typical formulation: g/ltr

Pancreatic digest of casein 

17.0 

Papaic digest of soya bean 

3.0 

Sodium chloride 

5.0 

Dextrose 

2.5 

Dipotassium phosphate 

2.5 


pH 7.3 ±0.2 

Applications


The main application for TSB is for performing microbial tests and for assessing the sterility of pharmaceuticals and medical devices, as well processes and operators. 

Tryptic Soy Broth can also be used at double strength to allow the addition of an equal miscible sample.

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

Related reading:

 

Appearance


The prepared media is a medium/dark straw clear liquid.  Double strength broth is dark straw in colour. 

 

Organisms & morphology

Tryptic Soy Broth will support growth of a wide range of aerobic and anaerobic bacteria if incubated under the right conditions.

A typical set of control organisms and growth associated with these is detailed in the chart below.

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 

Visible growth

Aspergillus brasiliensis

Visible growth


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Typical incubation parameters

As TSB is a general purpose highly nutritious medium, it can be incubated at differing temperatures depending on the target organisms. In sterility test applications it is common for bottles and vials to be incubated at 30-35°C for bacterial colonies and 20-25°C for mould and fungi.


Related reading:

Regulatory references

TSB 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

Casein Soyabean Digest Broth

Growth promotion

Aspergillus brasiliensis
Bacillus subtilis
Candida albicans

20 - 25°C for ≤ 5 days for fungi  

20 - 25°C for ≤ 3 days for bacteria  

 

EP Chapter Ref 2.6.12 Microbial examination of non-sterile products: Microbial enumeration tests

Recommended Culture Media

Property

Micro-organisms

Incubation Time & Temp

Casein Soyabean Digest Broth

Growth promotion

Bacillus subtilis
Pseudomonas aeruginosa
Staphylococcus aureus

30-35ºC for < 3 days


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Growth Promotion Testing: A Guide to Good Practices

This guide provides an overview of key considerations and best practices when undertaking growth promotion testing (GPT).


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