SOP: Thermometer Calibration Checks (Free)

SOP – Thermometer Calibration (Daily Checks)

A thermometer that’s two degrees out can pass unsafe food or fail safe food – either way you’re in trouble. This SOP covers the quick daily accuracy checks; the full lab calibration schedule lives in the calibration PRP.

SOPs only work if people actually read them. Train each operator, get the read-and-understood signature, and keep the language as plain as the job allows – this isn’t the place to show off vocabulary.

1. Document control

2. Purpose

To verify thermometer accuracy before use each day (or per shift).

3. Scope

Covers all probe thermometers used for food safety checks at [site name].

4. Responsibilities

5. Materials and equipment

• Crushed ice and water (ice-point check)
• Clean container
• Daily check log
• Spare calibrated thermometer

6. Safety precautions

• Dry the probe before use on hot foods to avoid steam burns.

7. Procedure

Follow the steps in order. Steps marked [CHECK] are the ones people skip under pressure – don’t.

1. Make an ice slurry: fill a container with crushed ice, add just enough cold water to fill the gaps, stir.
2. Insert the probe into the centre of the slurry without touching the container; wait for the reading to stabilize.
3. Accept 0 °C +/- [1 °C, or your criterion]. Record the reading. [CHECK]
4. Alternative: boiling water check at 100 °C (adjust for altitude per your procedure).
5. If outside the limit: quarantine the thermometer, label it clearly, and notify QA – then assess any food checked with it since its last good check. [CHECK]
6. Use the spare calibrated thermometer in the meantime.
7. Never adjust a thermometer’s calibration yourself unless trained and authorized.

8. Records

• Daily thermometer check log
• Out-of-tolerance investigations

9. Revision history

Approval and control

Keep completed forms for [Define retention period, e.g., 2 years beyond shelf life] at [defined location] – and make sure someone besides you knows where that is.