Cold chain.Preservation refrigerated and frozen food

The cold chain is the set of refrigeration techniques that enable a batch of foodstuffs to retain its market value and be maintained in hygienic conditions until it is used by consumers or industrial processors [BE 9 766] .

There is no such thing as a standard cold chain. The cold chain covers the entire food chain, from harvesting, picking or the end of product manufacture, to packaging prior to the actual application of cold, with the lowering of temperature (refrigeration or freezing) and maintenance of storage temperature, right through to use by the consumer.

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 to be applied to a healthy product, because cold cannot improve the initial quality of the product;

• early cold, to be applied as soon as possible after harvesting or manufacturing the finished product;

• continuous cold to be maintained until the end of the product's life; it is this last criterion that leads to the notion of a "cold chain".

The application of cold to foodstuffs is the only preservation process that does not, in the case of refrigeration, or only slightly, in the case of freezing, denature the foodstuff. Lowering the temperature of a foodstuff slows down the biochemical reactions that take place within it. By slowing down the metabolism of living plant organs, refrigeration preserves their nutritional reserves and keeps them "fresh".

Slowing down the metabolism of micro-organisms limits their growth and the associated deleterious and pathogenic effects. Under no circumstances can the application of cold "improve" the initial quality of the product. The disruptive effect on micro-organisms merely results in "dormancy". On the other hand, cooling too early and too quickly can disrupt the metabolism of animal and plant tissues to the point of causing undesirable phenomena such as meat hardening, or "cold diseases" of plant organs kept too long below a critical temperature.

The foodstuffs that enter the cold chain are of animal and vegetable origin. Their degree of processing ranges from the raw material – animal carcasses, plants after harvesting more or less trimmed – to...