For a food cold chain, the measurement file should identify the shipment and the conditions monitored. FAO's HACCP monitoring guidance addresses method, frequency, responsibility and record review together. Build a traceable path from the written product requirement to the measurement and decision record.
Start with the decision. A product requirement or critical limit determines the meaningful measurand. Do not treat air, surface and product temperature as interchangeable; link door openings, loading and waiting events to the same timeline.
Choose a representative point. Doors, airflow, loading layout and ambient conditions can affect temperatures at different points. In a mapping or placement study, consider both excessively warm and excessively cold locations for the product. Review whether previous points remain representative when load, packaging, air paths or seasonal conditions change. Define the product, surface or air measurement and sampling method against the decision it must support.
Preserve device and raw-file identity
Record device identity, channel, calibration status, logging interval, time zone and start/end times. Preserve the raw file and identify any processing applied to a report or converted copy. The Thermo King Precedent manual, pp. 125-129 treats return-air readings separately from cargo checks. A position drawing or photograph helps show which location the report describes.
| Evidence step | Information to retain | Review question |
|---|---|---|
| Criterion | Product/lot and written temperature condition | Which limit and measurement method apply? |
| Location | Air/surface/product, position and load layout | Does this point represent the load and risks? |
| Device | Identity, channel and calibration record | Is it suitable for the range and method used? |
| Time and data | Time zone, logging interval, raw file and gaps | Which period is actually covered? |
| Review | Reviewer, findings, decision and basis | Is any information or action still outstanding? |
Separate monitoring, verification and validation
The FDA-hosted HACCP guidance describes verification as plan and implementation checks beyond monitoring. Monitoring gathers the planned trip data. Verification includes checking that the plan is followed and reviewing its records. Validation assesses the scientific and technical basis for the plan to control hazards. The guidance discusses reassessment following unexplained failure or significant product, process or packaging changes. This food HACCP framework does not turn one temperature graph into qualification of an entire route.
Link a certificate or equipment class to the relevant equipment document, and the actual journey to loading, measurement and receipt records. Keep missing data visible. An incident report and period review can reference the same record IDs. Assess process restoration separately from affected-product disposition (FAO corrective-action guidance).
