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Expansion of the Perfringens Predictor Model to Include pH, Nitrite and Salt Concentrations in its Predictions

Institutions
Institute of Food Research, UK
Start date
2005
End date
2006
Objective
Project B14009 has developed a user-friendly software tool (called Perfringens Predictor) that predicts the growth of Clostridium perfringens during the heating/cooling of meat.

The Perfringens Predictor model enables the user to input temperature profiles into an Microsoft Excel spreadsheet and then provides a prediction of the growth of Clostridium perfringens under the specified dynamic cooling conditions. It also provides interpretation advice about the safety of the specified cooling profile.

The software and user manuals are available and can be downloaded from the Institute of Food Research website (see below).

The current version of the Perfringens Predictor model allows the user to input temperature during cooling, but does not allow the user to vary the pH, nitrite and salt concentrations. Current predictions are given under optimal conditions (pH 6.0 – 7.0, high water activity and no nitrite).

However, the food industry have indicated that the pH of meats could be as low as 5.7 and the salt concentrations as high as 3.1% with a concurrent reduction in water activity. Moreover, nitrite up to a maximum concentration of 150ppm can be added.

This project aims to expand the Perfringens Predictor model to enable users to take account of such pH, nitrite and salt concentrations of the meat when making predictions. Expanding the Perfringens Predictor will make the model a more useful tool, providing more accurate and realistic predictions when pH, nitrite and salt concentrations are not optimal.

More information
This project will use growth curves conducted at a single temperature to develop a dynamic model for growth that includes cooling temperature, pH, salt and nitrite.

Existing growth data from ComBase will be supplemented with 30 new growth curves. The model will then be validated by comparison with literature data and new data generated in this project.

New data will be generated under 20 different sets of pH/salt/nitrite and heating/cooling conditions. The user-friendly software will be revised to enable the user to input pH/salt/nitrite concentration. The major findings and user-friendly software will be widely disseminated.

The final report, "Expansion of the Perfringens Predictor Model to Include pH, Nitrite and Salt Concentrations in its Predictions" is available at Foodbase, an open access repository of the FSA.

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
B13005
Categories
Food Preparation and Handling
Clostridium