Cold chain: how to transport food and medicines without breaking the temperature

A refrigerated cargo is lost in a failure of minutes that nobody saw. The cold chain is the sum of all its links, from the supplier's cold store to the customer's, and it takes only one to fail.

What a reefer container does

A refrigerated container (reefer) maintains the cargo's temperature; it does not lower it. If goods are loaded warm, the unit does not have the power to cool them in time. So the cargo must be pre-cooled to transport temperature before loading, and the container pre-inspected before loading. As a rule the empty container is not pre-cooled, because opening the doors in warm air produces a lot of condensation; the exception is cargo moving straight from a cold store into the container. Always follow the carrier's instructions.

Cold air circulates underneath, through the T-floor, and rises along the sides. If cargo blocks that circulation, areas are left uncooled. Cargo is always stowed within the marked load line, with space left next to the walls.

Reference temperatures

• Frozen: −18 °C or lower, according to the product specification.
• Chilled: it varies by product. Fresh meat and fish, dairy and many fruit and vegetables sit between 0 and 8 °C, each with its own ideal range.
• Medicines: storage conditions (refrigerated or controlled room temperature) are set on the label and in the product dossier. The temperature is the one on the label, not a general rule.

Tropical fruit can suffer chilling injury if carried below its limit. Colder fruit does not always last longer.

Where the chain breaks

• Waiting at terminals with no power connection, or with the connection interrupted.
• Transfers between truck, warehouse and ship, with the door open or the cargo standing in the sun.
• Late documents: if the container awaits customs clearance, the reefer keeps consuming power and incurring demurrage.
• Power failures in land transit, mitigated by attached generators (gensets).

Monitoring and proof

Temperature data loggers inside the cargo and in the container document the journey and serve as evidence in a claim. For medicines, the European Union's Good Distribution Practice guidelines require qualified systems, written procedures, temperature control and traceability across all links. Those distributing medicines to Angola or from Portugal should ensure logistics partners meet these requirements and that the destination accepts the product, with the registration and authorisations of the competent regulator.

Questions to ask the forwarder

1. Was the container pre-inspected, with a report, and does the cargo arrive already at transport temperature?
2. Is power connection guaranteed at all waiting points, including the transit port?
3. Are temperature loggers supplied and who takes the final reading?
4. What is the plan in case of delay or breakdown, and who decides and pays?
5. Does the insurance cover loss of temperature or only physical damage? Many policies exclude it unless expressly requested.