When should thermometers be re-calibrated?

Thermometers should be re-calibrated in several situations to ensure they provide accurate readings, which is crucial for food safety. The correct answer encompasses multiple scenarios where re-calibration is necessary.

When a thermometer has been recently dropped, it may become miscalibrated due to the impact, affecting its accuracy. This is particularly important because an inaccurate thermometer could lead to improper cooking or storing temperatures, putting food safety at risk.

Additionally, if a thermometer is used for extreme temperatures, such as very high heat or very low temperatures, it can also affect the calibration. For instance, thermometers designed for one temperature range may not function correctly outside their intended use. Regularly checking and recalibrating ensures it remains precise within its operational limits.

Lastly, even if a thermometer hasn't been used for an extended period, external factors such as temperature fluctuations or humidity may impact its calibration. Regular checks are essential after long periods of inactivity to confirm that it still provides accurate readings.

Thus, the answer encompasses all these situations, highlighting the importance of re-calibrating thermometers to maintain accuracy and ensure food safety practices are upheld.