When the heat is on: why a heatwave is the real test of a cold chain

A heatwave is wonderful for almost everyone except a pallet of fresh produce. When temperatures spike across the UK the way they have this week, the part of the supply chain that usually goes unnoticed, the cold chain, suddenly has nowhere to hide.

For perishable goods, the cold chain is the unbroken run of controlled temperature from the moment produce is harvested to the moment it reaches a shelf. Strawberries, leafy salads, soft fruit, flowers, chilled and frozen lines: every one of them has a temperature band it has to stay inside, and the clock on quality starts ticking the instant it drifts out. In ordinary weather, there’s a little slack in the system. In a heatwave, that slack disappears.

The risk isn’t usually the reefer unit itself; modern refrigerated trailers are more than capable. The risk lives in the gaps. Product sitting on a sun-baked dock waiting to be loaded. A trailer that wasn’t pre-cooled before the pallets went in. A delay at a port or a border exposes the goods. A door open a few minutes too long during a handover. Each gap is small on its own; in 30+degree heat, they stack up fast, and the difference between premium produce and a written-off load can come down to a single weak link.

Protecting integrity through a hot spell isn’t luck, it’s discipline at every stage:

• Pre-cool everything. Trailers chilled to temperature before loading, so produce never has to fight to bring the box down.
• Load fast, load cold. Minimise the time product spends out of a controlled environment, especially on exposed docks.
• Monitor end to end. Continuous temperature logging means a drift is spotted and corrected in transit, not discovered on arrival.
• Plan for delay. Summer brings traffic, congestion and slower border flows. Build contingency in before it’s needed, not after.
• Tighten the handovers. The riskiest moments are the transfers between parties. Clear responsibility at each one keeps the chain intact.

There’s also a commercial point that’s easy to overlook. A broken cold chain doesn’t just cost the value of the goods; it costs the customer relationship, the reputation for reliability and, increasingly, the sustainability credentials that come from not sending perfectly good food to waste. Getting it right in the heat is as much about trust as it is about temperature.

For perishables, the cold chain isn’t part of the product. In a very real sense, it is the product. That’s the principle behind every temperature-controlled load we move, and it’s never more important than on the kind of week the UK is having right now.

Moving fresh produce or other temperature-sensitive goods this summer? Talk to us before the next hot spell, not during it.