Perfringens Predictor is intended for prediction of the growth of C. perfringens during the cooling of meat and poultry that has been heat-treated at 70-95°C. The model has been validated for cooked, cured and uncured meat and poultry products, and the Perfringens Predictor can be used as part of the USDA-FSIS Compliance Guideline for Stabilization of Fully and Partially Heat-Treated RTE and NRTE Meat and Poultry Products.

The model is based on the publication by Le Marc, Y., Plowman, J., Aldus, C.F., Munoz-Cuevas, M., Baranyi, J., and Peck, M.W. 2008. Modelling the growth of Clostridium perfringens during the cooling of bulk meat. International Journal of Food Microbiology 128: 41-50, which was improved based on a published article by Mohr, T.B., Juneja, V.K., Thippareddi, H.H., Schaffner, D.W., Bronstein, P.A., Silverman, M., and Cook, L.V. 2015. Assessing the performance of Clostridium perfringens cooling models for cooked, uncured meat and poultry products. Journal of Food Protection 78: 1512-1526.

Predictions of the C. perfringens concentration are made from the time vs. temperature profile measured during the cooling of cooked meat or poultry. Temperatures should be measured in the center (warmest) part of the meat or poultry.

Each successive temperature can be less than, equal to, but no more than 5.6°C higher than the previous temperature. The meat or poultry must be cooled to at least 15°C for the prediction to be given. The profile can be typed directly into the cells, or copied and pasted from another application (e.g. Excel spreadsheet, text file).

Please note that the time unit is hours, and temperature is in degrees Celsius (°C). The initial time must be zero hours, and the temperatures values must be in the range of 0°C to 95°C. A minimum of five time/temperature points are required, with no more than a total of 500 points (including time=0).

You must input a pH value (5.2 to 8.0) and salt concentration (0 to 4%), and indicate if the meat is cured or uncured. The cured meat option should only be used if the initial concentration of sodium nitrite is 100 ppm or higher and the residual sodium nitrite concentration is 10 ppm or greater.

The time vs. temperature profile and the predicted growth of C. perfringens is displayed on the Chart and in the Data tab. The temperature scale appears on the right hand Y-axis, and the plot is in red. The left hand Y-axis is the scale for predicted increase in C. perfringens , and the plot is a solid blue line. A horizontal black line shows a predicted 1 log10 increase in concentration of C. perfringens.