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Develop and Validate an Immunological Method for the Detection and Characterisation of all VTEC in Food

Institutions
Institute of Food Research, UK
Start date
1999
End date
2002
Objective

The objective of the project is to develop an immunologically-based method for the detection of all VTECs, which are of importance in human illness.

The method is based on dipstick technology whereby the dipstick will be coated with several key antibodies able to detect VT1, VT2, somatic antigen of serotype O157 and the attaching and effacing factor. The presence of these factors will not only permit the screening of foodstuffs for the presence of all VTECs but will also permit partial characterisation of strains which will aid the epidemiology of VTEC.

The method will be semi-rapid although it is anticipated that some culture stage will be required. Importantly, it will be suitable for use by surveillance laboratories.

This project aims to fulfil the recommendation of the ACMSF who, in their 1995 report on VTEC, recommended that Government fund research into the development of a rapid method for the detection of all VTEC in foods and clinical samples.

The project will be sub-divided into five objectives. These are shown below:

  • Objective 1. Prepare a short report on the availability of immunotechnology-based diagnostic kits for the detection of verotoxins produced by E. coli O157:H7.
  • Objective 2. Produce and/or obtain antibodies to VT1, VT2, O157 somatic antigen and other selected virulence factors. Label antibodies and confirm the specificity and sensitivity of all antibodies and of suitability for intended purpose.
  • Objective 3. Develop an appropriate enrichment procedure and dipstick assay for detection of VT1, VT2, O157 somatic antigen and other selected virulence factors. This will include optimisation of the enrichment procedure, development of dipstick technology, confirmation of specificity and sensitivity of dipstick and confirmation of suitability for intended purpose.
  • Objective 4. Robustness testing with food and a three-lab food trial. This will include; preparation of Standard Operating Procedures (SOP) and test trial materials, conducting three-lab trial, evaluation of data from trial and assessment of fitness for purpose, modifications of enrichment procedure and dipstick assay as required.
  • Objective 5. Formal validation trial. This will include preparation of SOP and trial test materials, conduct collaborative trial, analysis of results and preparation of final trial report, submission of method for final approval.
More information
In the UK and overseas, there is an increasing occurrence of foodborne illnesses associated with verotoxin-producing E.coli (VTEC) which could lead to haemorrhagic colitis and haemolytic uraemic syndrome.

Current detection methods rely on detection of the serotype O157. However, it is acknowledged that at least 100 serotypes of E. coli O157 may produce verotoxins, hence the need to establish a method that will detect all verotoxin-producing E. coli rather than just those of the O157 serotype.

The importance of developing this method was recognised by the ACMSF in their 1995 report on VTEC.

Find more about this project and other FSA food safety-related projects at the Food Standards Agency Research webpage.

Funding Source
Food Standards Agency
Project number
B09010
Categories
Escherichia coli