The exact calibration schedule depends on the type of thermometer you use and how you use it. You should recalibrate your thermometers, following these criteria:

1) Digital thermometers (most common handheld pulp thermometers) every week to a month, depending on its quality and manufacturer specifications.

2) Bimetal thermometers, such as those in the grills with metal probes and analog indicators, before every shift.

3) Always calibrate new thermometers (except if you are provided with a certificate of calibration from the factory/manufacturer) or one that has been dropped, bumped or apparent damage is observed.

4) after using it to measure significantly different temperatures (e.g. cold vs a cooked product), which shouldn’t be applicable if only used in the cold room.

5) Last but not least, as I have mentioned above, consider following the manufacturer guidelines/instructions.

-- Irwin Donis-Gonzalez