Checking The Accuracy of your Thermometers and Probes

Audit standards regarding the calibration and control of measuring equipment (such as BRCGS Clause 6.4.2), state that measuring devices must be checked at a predetermined frequency and to a defined method traceable to a recognised national or international standard.

This means that regular verification is vitally important to ensure audit-compliance and that your thermometers are working correctly. If left unchecked, inaccurate readings could lead to major food safety issues, resulting in product recalls and serious risks to consumers.

Watch the video below for best practice tips on verifying the accuracy of your thermometers.

Video Transcript

It is important to check the accuracy of your thermometers regularly to ensure food safety is not being compromised.  Not only is this best practice and a legal requirement, it is also stipulated in recognised industry standards, this includes the BRC Global Standard for Food Safety Issue 8, which has a whole section dedicated to the calibration and control of measuring and monitoring equipment, such as thermometers.

This includes the following clause:

All identified measuring devices, including new equipment, shall be checked and, where necessary, adjusted:

  • at a predetermined frequency, based on risk assessment
  • to a defined method traceable to a recognised national or international standard where possible.

Results shall be documented. Equipment shall be readable and be a suitable accuracy for the measurements it is required to perform.

Klipspringer recommend you check or verify your thermometers daily or every shift. What is best for you will depend on your quality and CCP procedures on site. Here’s a few things to look out for when checking your thermometer accuracy.

First make sure you check your thermometer unit and your probe together. Both have their own accuracy tolerance so it is important to check the combined accuracy of the complete thermometer and probe. Bear in mind that the majority of accuracy drift is with the probe, so checking the thermometer alone, such as with test caps as these, is insufficient.

Second, check at two temperatures to check the range of the thermometer. This could be at 0 and 100 or whatever is applicable to your testing range. The exceptional quality of Klipspringer thermometers means that when your verification procedure confirms the thermometer is within spec at two temperature points, we can guarantee it is within spec across the whole range. This means checking at 0 and 100, for example, is sufficient for any applications where you may need to measure higher than 100 degrees celsius.

Third, you need a stable test medium, you need to make sure the temperature of whatever you use to test your thermometer is stable so that the thermometer can work properly. Using boiling water, for example, means you are chasing falling temperatures and this will likely result in inaccuracies.

Fourth, according to BRC Version 8, ‘It must be to a defined method, traceable to a recognised national or international standard where possible.’ In the UK, this would typically mean UKAS. Klipspringer recommend the most effective way to meet all of these criteria is with a heat source calibrator, such as the LazaPort8 Calibrator which I have here. This also gives you the ability to speed up your thermometer checks by checking probes simultaneously in these top ports here.

As well as checking your infrared thermometers against a known calibrated medium, which is highly useful for accurate infrared verification. The BRC Standard also states results should be documented, if you wish, you can use one of our free spreadsheet downloads to do this. If your thermometer reads outside of your site tolerance, it should be sent back to Klipspringer for assessment and repair. Pack it up and arrange free-of-charge collection using our returns link.

As always, please contact the Klipspringer Technical Team with any questions and we’ll be very happy to help.