CTemp: Centre Temperature Prediction for Packaged Foods

Process Establishment Example

This examples shows heat penetration data for a UT can (73 mm diameter, 115 mm height) of sliced carrots processed in an FMC reel & spiral simulator. The data set chosen for the predictions is the one that gave the lowest end of heating F₀ value.

The intended factory process must achieve a minimum end of heating F₀ of 8 minutes, using a process temperature of 122.0 °C. The simulator was held at around 121.5 °C for 12 minutes to get close to the F₀ of 8 minutes and generate the data for the predictions. The ‘screen print’ shows the heat penetration data and illustrates the variation around the 121.5 °C setpoint.

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The first graph below shows how close the match in temperatures for the measured heat penetration data was with those from the CTemp prediction. The calculated f_h value was 4.0 minutes. The F₀ at the end of heating was 7.0 minutes (12 minutes at 121.5 °C) and at the end of cooling it was 7.6 minutes. This process needs to be transferred to the factory simulator, after evaluating ‘worst case’ conditions.

The second graph below shows the predicted profile alone, using the retort profile from the CALCULATE screen as the input. This is now ready to make the changes to achieve an end of heating F₀ value of 8.0 minutes.

The third graph below shows the prediction from the amended retort profile. A processing temperature of 121 °C was chosen for the predictions, which allowed the temperature of the factory cooker to drop by 1 C° from the 122 °C setpoint during normal operation. This was done to allow a safety margin in the operating temperature of the reel & spiral cooker without the need to refer the batch as a process deviation. The suggested process was 15 minutes at 122 °C (simulated at 121 °C) to achieve F₀ 8 end of heating.