the thermal process validation demonstrates that a heating process – such as pasteurization, sterilization, baking, cooking, or hot filling – reliably achieves the desired germ reduction. Since heating steps are frequently used as CCP If they are classified, their validation is among the most important evidence in the HACCP system. It is a special case of the general Validation and Verification.
The basis is microbiological parameters from the food microbiology:
- D-value: Time at a specific temperature that reduces the germ count by 90 % (a power of ten)
- z-value: Temperature change that alters the D-value by a factor of 10
- F-value or P-value: cumulative killing effect of a process, relative to a reference temperature
In practice, temperature distribution and heat penetration within the product are measured (e.g., using data loggers at the "coldest point"), worst-case conditions such as maximum load or piece size are taken into account, and results are confirmed, if necessary, through challenge tests. Revalidation is required after changes to the recipe, packaging, or equipment; for the equipment itself, the Checklist for plant qualification. The procedure is explained step by step in the Training Validation & Verification of Thermal Processes.
