Cold chain: process and links

The cold chain is the set of refrigeration techniques that enable a foodstuff to retain its market value and be maintained in hygienic conditions until it is used by consumers or industrial processors .

The cold chain is a succession of operations carried out under controlled temperatures using refrigeration equipment, and is made up of various links (warehouses, vehicles, sales units, refrigerators, etc.) from the harvesting or manufacture of the product to its consumption. There is no such thing as a typical cold chain; depending on the type of link, it may be present in the logistics chain once or several times. The extent of the efforts made in the "upstream industrial links" governed by regulations depends, of course, on mastery of the final link (domestic refrigerators and freezers).

The cold chain has long been based on a "golden rule" enunciated by Alexandre MONVOISIN (1934), who formulated it in three major principles known as MONVOISIN's "refrigeration tripod":

• healthy cold: only healthy products should be kept cold;

• early cooling: refrigeration or freezing must be carried out as soon as possible, at an optimum temperature and at a cooling rate that respects the quality of the finished product;

• Continuous cold: maintaining preservation temperature is a "sine qua non" condition; it is this last criterion that leads to the notion of the "cold chain".

Controlling the food cold chain is first and foremost a public health issue, as it ensures that urban populations in particular are supplied with sufficient quantities of fresh, healthy foodstuffs. Around a third of the world's food production (5,500 million tonnes) is made up of perishable products (1,800 million tonnes), which should be kept cold, but only 22% is. The importance of an efficient cold chain clearly plays a decisive role in reducing losses.

Half of French food consumption is accounted for by cold-preserved foods: 90% of the mass is refrigerated and 10% frozen. While half of all fruit and vegetables are distributed "out of cold", due to their seasonal nature and natural tendency to deteriorate slowly after harvesting, the cold chain is essential for most fresh meat products, whose fragility must be protected as soon as possible after preparation.

There are two categories of food products to be kept at controlled temperatures: frozen products to be kept at –18°C or below, and chilled...