A food thermometer is a piece of equipment that allows the operator to take the temperature of food. There are different types of food thermometers including probe thermometers and surface or laser thermometers.
A common HACCP monitoring activity is temperature measurement. This can involve taking the temperature of a food product at receival, cooking, storage, cooling or reheating process steps and aims to ensure that the predefined critical limit is not exceeded. Critical limits based on temperature are commonly set to help control microbiological hazards. However, all of this work can be undermined if your thermometer has not been calibrated. In other words, your thermometer needs to be reading correctly.
Food thermometers need to be calibrated to ensure that they are working correctly and giving an accurate reading. The consequences of equipment not reading correctly can be devastating for a food business. It may be the difference between producing a safe product and producing a product that may kill a consumer. It can also leave the business open to litigation.
Two of the most acceptable methods to check the accuracy of your food thermometers is by boiling water and an ice water slurry. For the boiling water method, sit your food thermometer in boiling water. The reading should be 100 degrees Celsius. For the ice slurry method, the reading should be zero degrees Celsius.
If you find that the readings do not match 100 or zero, your food thermometer requires calibration. You may have the ability to undertake this adjustment in-house or you may need to send the equipment to an external calibration provider.
Frequency of Calibration
The frequency of calibration depends on several factors. These include:
- How often the food thermometer is used
- What the risk is to the food business
- Legal or regulatory requirements
- Customer certification requirements
Recording your results
Any calibration that is performed on your food thermometers should be recorded. As a general rule, calibration records will be reviewed as part of any third party HACCP certification. Records should be legible and include the food thermometer identification, result of testing and the person or company who undertook the test.