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Post Stress Detection of Cold and Hypochlorite Stress Proteins in Salmonella typhimurium

Institutions
University of Edinburgh
Start date
1998
End date
2001
Objective
This project aims to explore the responses of the foodborne bacterium Salmonella typhimurium to stress encountered during commercial food processing or storage

The approaches consist of:

  • Exploring the responses of S. typhimurium to hypochlorite (a sanitising agent) and refrigeration (temperatures of 4-8°C and 10°C), using 2D gel electrophoresis.
  • Determining how stress proteins which change during the stress period (refrigeration and hypochlorite exposure) relate to the overall cellular level of such proteins.
  • Determining whether proteins exist which have suitable properties as markers for reflecting the stress and identifying such markers.
  • Assessing whether a preliminary immunoassay could be developed, and the level of sensitivity of such an assay.
More information
Salmonella and Campylobacter are major causes of foodborne disease in the UK. The link between contaminated poultry and infection in humans is well known.

In order to cause infection in consumers, such organisms need to persist through the commercial processes used for food processing and storage.

Bacteria are known to be capable of adapting to many adverse conditions by inducing stress proteins, which minimise the harmful effects of the environment.

The risk of infection is thought to depend not only on the number of potentially harmful bacteria present on food, but also their status and ability to recover from sub-lethal stresses encountered during food processing.

To properly evaluate and reduce the overall risk to the consumer, it is important to dissect and assess the risk at each of the stages between the initiation of food processing through to consumption.

The fact that bacteria can alter their protein composition in response to the environment or any stresses they encounter means that stress-specific proteins may exist within these cells.

These proteins can be used as a quantitative marker of the number of harmful bacteria which exist on the foods, and what treatments or environments they have encountered. Such markers would reflect the stress history of the bacteria and the processing which they and the foodstuff have received.

The overall project aim is to explore the response of the foodborne bacterium, Salmonella typhimurium, to stress encountered during commercial food processing or storage.

The project will focus on characterising the change in protein profile, which occurs following exposure to the sanitising agent hypochlorite and to incubation at refrigeration temperatures, since these commonly feature during poultry processing.

The project also aims to determine whether stress proteins could be identified with suitable characteristics, so that they may have value as indicators of the stress history of the organism. If such markers are found, the project intends to determine their level of sensitivity.

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
B01008
Categories
Salmonella
Campylobacter
Bacterial Pathogens