A reading on a trailer’s air-temperature probe is not the temperature of your product. Air responds in seconds to a door opening; palletised food, with its thermal mass, takes far longer to move a fraction of a degree. Understanding that difference, and being able to evidence it, is what separates a load accepted with a note from a load rejected at the door.
Why air spikes when product doesn’t
Every time trailer doors open at a multi-drop delivery, ambient air rushes in and the air probe reads it immediately. The product inside a wrapped pallet is insulated by packaging, by its neighbours and by its own mass. Industry guidance (including BFFF’s work on frozen distribution) has long recognised that transient air-temperature excursions during door openings are normal operation, not evidence of a broken cold chain.
| What’s being measured | Responds to a door opening in | What it tells you |
|---|---|---|
| Trailer air temperature | Seconds | The environment right now |
| Product core temperature | Tens of minutes to hours | Whether the food was actually compromised |
What actually settles a dispute
When a load is queried at goods-in, the argument is won with records, not recollections:
- A continuous temperature trace for the journey. Not a single reading at the door, but the pattern: set-point held, brief door-opening blips, recovery each time.
- The delivery timeline alongside it, showing each spike aligns with a drop, not with equipment failure.
- Proof of delivery tied to the same consignment. One evidence chain, one reference.
That pattern (brief rise, quick recovery, product band never threatened) is the normal signature of a working multi-drop cold chain. A genuine failure looks different: a sustained climb with no recovery.
What to ask your carrier
If you move chilled or frozen goods, ask any carrier three questions: Is temperature recorded continuously against my consignment, not just the vehicle? Can you hand me the trace for a specific delivery, quickly, when a customer queries it? And does your team know how to read it, so they can tell a door-opening from a unit failure?
Igloo records temperature continuously against every chilled and frozen consignment and provides the evidence alongside electronic proof of delivery, so if a load is ever queried, the data does the talking. Ask us for a quote or see our accreditations.
