IFR Gel Cassette
Why the technique was developed
The growth of bacteria in foods is frequently predicted using data derived from their growth in liquid cultures. Whilst this is relevant to the growth of bacteria in most types of foods, it does not allow for the effects of immobilisation, and the subsequent growth as colonies as may occur in structured foods. The IFR Gel Cassette system allows the impact of immobilisation, such as decreased growth rate and restricted habitat domain, to be studied under controlled conditions.
The IFR Gel Cassette System is designed to enable the investigation of the growth of bacteria as colonies derived from single immobilised cells. The bacteria are grown in gelled microbiological culture medium and contained within a cassette formed between gas-permeable sheets. The technique has also been successfully used to grow both yeasts and filamentous fungi.
Benefits of the IFR gel cassette system
- allows monitoring of colonial growth where conventional techniques give a restricted view of actual behaviour
- provides a contained environment for added security in handling all micro-organisms including pathogens
- allows growth of bacteria, yeasts or filamentous fungi as immersed, immobilised colonies
- permits controllable spatial distribution of the cells and colonies
- allows growth of pure cultures, or interactions between colonies of different species
- autoclavable system
- provides a well-controlled growth environment, including:
- gaseous exchange through gas-permeable windows
- ample nutrient supply to the colonies
- easy adjustment of chemical conditions e.g. pH, concentration of sucrose, NaCl, organic acids, food preservatives etc.
- possibility of imposing chemical gradients within the cassette
- ease of preparation, with minimal stress applied to the inoculum
- applicable to a wide range of ecological studies
Practical issues
Preparation of the IFR Gel Cassette involves the combination of growth medium with the gelling agent. This is then inoculated with the desired micro-organism or combination of organisms, and loaded into the Gel Cassettes.
Temperature and environmental conditions within the Gel Cassette can be altered to suit experimental needs. Gradients can be introduced as a further development of the technique.
Growth of colonies can be measured after quantitative recovery of cells using traditional microbiological methods such as viable or total counting, or by more sophisticated instrumental analysis such as flow cytometry or FACS. Alternatively, the Gel Cassette may be used as a microscope slide and in-situ, real-time, non-invasive microscopical techniques can be applied such as:
- measurements of colony diameter
- confocal microscopy
- fluorescence microscopy
- fluorescence ratio imaging
- expression of reporter genes
The Cassette can be opened easily to allow portions of the gel to be removed and used in other forms of analysis.
The kit contains all of the necessary equipment over and above that which would normally be found in a microbiological laboratory. We assume that you will have access to autoclaves and pH meters etc.
IFR offers training in the use of the IFR Gel Cassette system. This may be tailored to your needs and application, either at your premises or here at the Institute of Food Research.
If you have a particular interest in food microbiology, you may like to consider joining the Predictive Microbiology and Risk Analysis Cluster of IFR's Food and Health Network.
Contact details
For further details, contact Tim Brocklehurst at:
Institute of Food Research
Norwich Research Park
Colney
Norwich
NR4 7UA
UK
Tel: +44 (0) 1603 255399
Fax: +44 (0) 1603 507723
e-mail: Tim.Brocklehurst@ifr.ac.uk
Please note:
Registered Design No. 2104251
This product is subject to modification without notice. The information is provided on the basis of our current knowledge; you should verify the adequacy of this product in your own situation since we cannot accept responsibility for results over whose production we have no control.
