The requirements for a measuring instrument used on quick-frozen food are set out in Annex II, clause 5, of Turkish Food Codex Communiqué 2001/45.
| Requirement | Value |
|---|---|
| Response time | 90 % of the difference between first and final reading within 3 minutes |
| Accuracy | ± 0.5 °C between -20 and +30 °C |
| Drift | No more than 0.3 °C in operation |
| Display resolution | 0.1 °C |
| Calibration | Valid certificate |
In the worst case accuracy and drift lean the same way and the uncertainty is 0.8 °C. A reading of -18.5 °C does not prove the product met the -18 °C limit, because the true value could be -17.7 °C; a reading of -19.0 °C does show it stayed inside.
When ice cream carriage temperature comes up the first question is the same: with which instrument, from where, and after how long did you take the value.
In the measurement a pre-cooled probe goes 2.5 mm below the surface and the value is read once it is steady. An infrared thermometer held against the surface cannot do this, but it is useful for finding the warmest carton on a pallet.
Devices that record ambient temperature in the store and the body fall under Article 4 of Communiqué 2014/48 instead: they need documents showing compliance with TS EN 12830, 13485 and 13486.
