Which statement correctly describes thermometer calibration frequency and methods?

• A. It should be calibrated weekly or before each shift
• B. It should be calibrated before each shift using ice-water and boiling-point methods
• C. It should be calibrated only when readings seem off
• D. It should be calibrated daily without reference to methods

Answer: (B)

Thermometer calibration is about ensuring temperature readings are accurate for safe handling of foods. The best practice is to calibrate before each shift, so you’re starting with trustworthy readings during the whole shift. Using two fixed reference points—the ice-water bath and the boiling-water point—provides reliable checks: the ice-water method should read 0°C (32°F), and the boiling-point method should read 100°C (212°F) at sea level. If the thermometer doesn’t match these known points, you adjust it and recheck until it does. This two-point method catches both small offsets and misreads across the range, giving confidence that temperatures used for cooking, cooling, and holding are accurate.

Calibrating only weekly, or only when readings seem off, leaves room for unnoticed drift that can compromise safety. Calibrating daily without specifying the reference methods isn’t ensuring you’re using standard checks. So calibrating before each shift using ice-water and boiling-water checks is the correct approach.