What is the cold chain? 

The cold chain is the unbroken sequence of refrigerated production, storage, transport and sale for temperature-sensitive products. Each link in the chain keeps the product within a specified temperature range. A single interruption can compromise the safety and shelf life of the entire batch. 

Why an unbroken chain is crucial 

Micro-organisms grow rapidly as soon as the temperature rises above the critical threshold. Even a brief interruption accelerates spoilage, even if the product is subsequently cooled again. 

Moreover, temperature damage is invisible. A product may look fine whilst its shelf life has already been reduced or its safety compromised. 

That is why a simple rule applies in the cold chain: the chain is only as strong as its weakest link. Control revolves around every transfer between links. 

The links in the cold chain 

The chain runs from producer to consumer and consists of fixed links: 

• Production and processing: products are returned to the target temperature immediately after processing. 

   

• Refrigerated storage: cold stores and freezer rooms maintain a constant temperature, which is recorded. 

   

• Transport: refrigerated lorries and refrigerated containers bridge the distance between links. 

   

• Transhipment: loading, unloading and cross-docking are the most vulnerable points in the chain. 

   

• Point of sale: refrigerated display units and freezers safeguard the final stages of the journey to the consumer. 

Temperature zones by product group 

Each product group has its own zone. The table shows standard guideline values in European practice; legal maximum limits vary by country and category. 

Set out the temperature zones for your product range in your HACCP plan and link them to measurable limit values. 

Packaging and containers in the cold chain 

Cooling can be active or passive. In active cooling, a cooling unit blows cold air through the room or vehicle; in passive cooling, insulation and cooling elements maintain the product’s temperature. 

With active cooling, the carrier determines how effectively that cold air reaches the product. Crates with perforated walls and an open base allow the air to flow freely past the product, enabling it to reach and maintain the correct temperature more quickly. 

The container must also be able to withstand these conditions itself. Depending on the type, Didak Injection crates can be used at temperatures ranging from minus 18 to plus 40 degrees Celsius and can therefore withstand both the freezer and hot transhipment areas without warping or breaking. 

Hygiene is also a major consideration in a supply chain full of condensation and product residues. Didak Injection crates are industrially washable up to 55 degrees Celsius, dry quickly thanks to their smooth surface and, under normal use, have a service life of well over fifteen years. 

Crates for fish, meat and fresh produce 

The most stringent requirements in the cold chain come into play with fresh produce. Didak Injection therefore manufactures specific crates for fish, meat and poultry, bread and fruit and vegetables, each tailored to the temperature zone and hygiene requirements of that product group. 

Fish crates, for example, are available with an optional perforated base, allowing meltwater from the ice to drain away immediately and keeping the product cold and dry. Fruit and vegetable crates with ventilated walls maintain the airflow that keeps soft fruit and vegetables fresh. 

All crates comply with Euronorm dimensions and feature label integration via barcode or RFID. This ensures they are compatible with pallets, washing systems and the temperature monitoring described in the following section. 

The cost of a broken supply chain 

A temperature deviation rarely affects just one product. Usually, the entire consignment or even a day’s production has to be rejected, as no one can prove which part remained safe. 

In addition to the direct write-off, there are indirect costs: urgent deliveries, customer claims and, in the worst-case scenario, a recall resulting in reputational damage. 

Waste is also a factor. A seamless cold chain extends shelf life and thus reduces the amount of food that never reaches the shop or the consumer. 

Legislation and standards relating to the cold chain 

The legal basis lies in the European Hygiene Regulation (EC) No 852/2004, which mandates that the cold chain must not be interrupted. National food legislation specifies the precise temperature limits for each product category. 

For international refrigerated transport, the ATP Agreement also applies. This sets out requirements for the insulation and refrigeration capacity of vehicles and containers used for perishable foodstuffs. 

In the pharmaceutical supply chain, Good Distribution Practice (GDP) fulfils this role. Here, even stricter requirements apply to the qualification of transport vehicles and to the documentation of any temperature deviation. 

Monitoring and recording 

Without measurement, there is no proof of a closed chain. Data loggers and sensors record the temperature per compartment, vehicle or even per carrier. 

Crates fitted with RFID link that data to a specific batch and location. In the event of a deviation, you can immediately see which products have been outside the temperature zone and which routes a crate has taken. 

View our crates for fish, meat and fruit and vegetables