Cold Chain Basics: How Frozen Seafood Stays Safe in Transit

Frozen fish and seafood such as mackerel, herring, sardines, salmon and tuna can travel thousands of kilometres and still arrive in excellent condition, but only if the cold chain is never broken. Here is how it works in practice.

Freeze quickly, store cold

Quality starts with fast freezing soon after catch or processing, followed by storage at a stable low temperature. A common requirement for frozen fish is −18°C or colder, and some premium products such as tuna are stored at much lower temperatures.

Use pre-cooled reefer containers

Refrigerated containers (“reefers”) should be cleaned, inspected and pre-cooled before loading. Goods must be loaded quickly and stacked so that cold air can circulate, without blocking the air channels or exceeding the load line.

Monitor temperature during transit

Data loggers or reefer monitoring systems record temperature throughout the journey. This record is valuable proof if a quality dispute arises, so ask your supplier or forwarder to share it.

Minimise handling and waiting time

Every transfer between ship, truck and warehouse is a risk. Plan customs clearance and unloading in advance so that frozen goods do not wait on a quay or in a yard.

What to look for on arrival

• The recorded temperature during transit and at unloading;
• The condition of cartons: no wetness, staining or deformation;
• Product appearance: heavy ice crystals, dehydration (freezer burn) or a visible thaw line suggest temperature abuse;
• Glaze and weight, which should match the specification.

Documents for fish imports

Besides the usual trade documents, wild-caught fish imported into the European Union generally needs a catch certificate, and fishery products need the appropriate health certificate. Check requirements with your customs broker before shipment.