Refrigerated transport : What you must keep in mind

At a time like the present, when consumers know that they can have everything at their fingertips in just a few hours, road transport of goods takes on, if possible, a more important role in the supply chain that goes from the producer to our homes. But where the carrier really plays a fundamental role is in the transport of perishable or fresh goods that require a special type of transport. We are talking, of course, about refrigerated transport.

This is the form of shipment that must be used to ensure that those products that have to travel at a controlled temperature do so with maximum guarantees and arrive at their destination in perfect condition. This requires vehicles capable of covering the long distances that are sometimes needed to move certain goods and, of course, a specific refrigeration system that will be built into the vehicle itself, responsible for maintaining that optimum temperature.

This must meet a series of requirements that were established decades ago and are included in the ATP or "Agreement on the International Carriage of Perishable Goods and on Special Vehicles used for such Carriage". An international agreement, signed in Geneva in 1970 and still in force, whose objective is to guarantee to the final consumer that the food arrives in adequate hygienic conditions, ensuring that the vehicles that carry out this transport comply with the technical conditions established by the ATP.

Thus, trucks transporting perishable goods on the roads of these territories are required to be identified by an ATP plate to identify that the truck is isothermal and respects the cold chain (an uninterrupted series of refrigerated production, storage and distribution activities, together with associated equipment and logistics, that maintain quality through a desired low temperature range).

What products do refrigerated trucks carry?

Although there are many types of refrigerated trucks, they all share one characteristic: their low heat transfer capacity that prevents weather conditions from influencing the interior temperature. In this sense, the ATP establishes a list of the temperatures at which the different goods classified as perishable must be transported :

• Frozen creams: -20 ºC.
• Frozen or deep-frozen fish, mollusks, crustaceans: -18 ºC.
• Deep-frozen products in general: -18 ºC.
• Other frozen products: -12 ºC.
• Frozen butter: -10 ºC.
• Frozen butter: -10 ºC.
• Butter: +6 ºC.
• Industrial milk: +6 ºC.
• Game products: +4 ºC.
• Milk in tanks: +4 ºC.
• Refrigerated dairy products: +4 ºC.
• Poultry and rabbits: +4 ºC.
• Red meat offal: +3 ºC.

Typology of refrigerated trucks

Even so, not all trucks are authorized to transport all types of goods since, as we have seen, each food or range of products requires specific temperatures. Therefore, we must pay attention to the following typology of transport vehicles:

• Isothermal truck: The box is built with insulated walls, including doors, floor and roof, which limits heat exchange between the interior and the exterior. 
• Refrigerated vehicle: A type of isothermal vehicle which, thanks to a cold source, makes it possible to reduce the temperature inside the empty body and then to maintain it for an average outside temperature of 30°C to -20°C maximum. 
• Refrigerated vehicle: In this case, we are talking about an isothermal vehicle that incorporates a cold production device, and allows, with an average outside temperature of 30°C, to reduce the temperature inside the empty body and to maintain it between 12°C and -20°C. 
• Heating vehicle: This type of isothermal vehicle is equipped with a heat-producing device that raises the temperature inside the empty body and maintains it for at least twelve hours at a value not lower than 12°C. 

Although the vehicles mentioned above are the most common for refrigerated transport, it should be noted that there are others adapted to more extreme requirements. Such as refrigerated with dry ice, trucks that normally have a temperature of -78 degrees and the cold is generated by sublimation (the passage from the solid state to the gaseous state). These have ice blocks of different sizes, but in no case can they exceed ten kilograms in weight. A similar system is found in the carbonic snow system, whose refrigeration is also produced through sublimation, the snow appearing due to the carbon dioxide that is in a liquid state. 

How to keep a refrigerated vehicle in good condition? 

Now that we know the types of refrigerated trucks... the most important part comes: how to keep them in good condition so that their work is guaranteed. Something not to be trifled with and for which we must be very strict. In fact, the conformity of special vehicles for the international transport of perishable goods must be checked by an independent and authorized entity before they are put into service and periodically, at least every six years. Also, each time the goods are loaded and unloaded, temperature checks must be carried out and records kept. 

Of course, the interior must be completely airtight and made of extremely corrosion-resistant and 100% waterproof materials. This ensures that the goods are not damaged in transit. The surface must also be suitable for air to circulate properly between them. Of course, the box must be completely isolated from the rest of the vehicle. 

If we are the ones who hire the service, special attention must be paid to ensure that the suppliers refrigerate the unit beforehand and regulate the temperature appropriately for each product (here it is essential to have a thermostat), in addition to making sure that they check that the goods are packed correctly before being shipped and that the goods are loaded onto the vehicle as quickly as possible and without leaving the doors open for a long time.

It should be remembered that, before loading, the truck must have been cleaned and disinfected to avoid contamination of the cargo with bacteria, chemicals or bad odors. Next, attention must be paid to the placement of the cargo, making sure that the boxes or pallets do not obstruct the free flow of air inside the trailer. Likewise, when receiving the goods, the truck driver must make sure that the cold chain has been maintained, checking that the temperature inside matches that indicated on the transport label. 

Only by complying with all these measures to the letter will we achieve safe refrigerated transport.