BRC Global Standard for Food Safety, Issue 8 - Clause 5.2.5: Cooking (heating) instruction validation
Instruction validation is the use of a methodology, procedure or protocol to help ensure that the cooking or heating instructions for a food product are developed and tested to achieve a ‘safely’ heated product for consumers to eat of acceptable quality. The key aim is to ensure the target product will be sufficiently heated to destroy and remove any appreciable risk of food poisoning from key heat resistant pathogenic bacteria which may, or may not be present in the food, especially those able to grow at (chilled) storage temperatures. The target organism for destruction is usually Listeria monocytogenes, but other micro-organisms may also be targeted e.g. viruses in shellfish.
Successful instruction validation is usually defined as a test challenging the cooking or heating instruction. This ‘test’ should be performed using calibrated devices, appliances and worst-case samples with sufficient replicates to allow an acceptable degree of confidence in the results.
An instruction is considered acceptable if it delivers sufficient temperature and time at that temperature to destroy the target organism (Listeria monocytogenes). A 6-log reduction is usually considered an acceptable safety margin i.e. if there were a million units of the viable bacteria, the thermal (heat) process would need to be sufficient to reduce the level to just one unit. This can either be measured by inoculating the food with the target bacterial organism (or one with similar death kinetics) and measuring the reduction in the viable target bacteria after heating the product. An alternative method is to measure the temperature (and time at that temperature) and then calculate how many of the target bacteria would have been killed if they had been present. This method is easier to perform and most likely to be used. For the purposes of instruction validation discussed within this document, only the temperature and time method will be considered as it can be performed using standard equipment that should be available in most food production premises.