For many food processors HACCP principles as detailed in Table 1, are commonly implemented. A critical point of the process when cooking or chilling food is the manual testing of product temperatures at the exit of the oven or chiller with a hand-held thermometer. This action in itself is easy to implement but does have some issues that must be managed with care.
- Does the exit temperature accurately reflect the peak product temperature?
- Is the operator measuring the correct part of the product? ie core or surface
- Is the operator measuring products over the entire cook / oven area - top and bottom of a static food rack or left to right on a conveyorized oven?
- Is manual recording of product temperature readings acceptable? It has the potential for error in transposing readings from a digital display to QA test sheet.
The greatest deficiency of the use of a hand-held thermometer is that it only provides a point measurement that is post process. If the product core temperature is greater than the specified safe minimum everything is fine and processing can continue with confidence. In the event of the core temperature being less than the target value we can see from Table 1 principle 5, that in the event of a product failing to meet the critical limit the system must be analyzed and a corrective action implemented. An undercooked product could result from the oven being run using incorrect recipe parameters, or the oven itself not performing correctly. What options are left to the QA manager when he faces a situation where the product core temperature is too low yet the oven controller is set correctly?
The reading from the oven controller display does not give the whole picture of what is happening in the oven. The oven temperature control sensor is often located away from the product and cannot reflect the temperature experienced by the product. The temperature experienced by the product can be affected by many variables including air velocity and moisture level, and may be independent of the oven set point. Poorly balanced air flow within an oven can result in temperature imbalance resulting in significant different cook rates dependent on position within the volume of the oven
The use of a "through process" data logger monitoring the product temperature throughout the cook and chill process can be used to rapidly find the cause of an incorrect product exit temperature thus enabling process engineers to follow principle 5 (regarding establishing corrective actions). It can also form part of the regular measuring procedure compliant with principle 4, see table 1
In addition to compliance with HACCP guidelines, a "through process" profiler will help in establishing more efficient recipes, confirm effective corrective actions and support a quality system that is preventative rather than reactive.