Just as there is a supply chain that ensures operability in industrial and commercial processes, there is a cold chain that guarantees the preservation of food, pharmaceutical, medical and chemical products. This temperature control, from processing to disposal by the final consumer, prevents the deterioration and decrease in the properties of said products. In short, it is about maintaining their quality and avoiding the losses that would be caused to the production and commercial companies if they were damaged.

Read on to understand a little more about the importance of persevering in this food cold chain.

What is the cold chain?

In the specific case of food, the cold chain consists of permanent control of low but adequate temperatures in all stages of the supply chain of a product. That is to say, from its processing, through its storage and transport, to the shelf of the commercial premises where the client will acquire it.

The reason why it is called a chain is that a series of processes occur in it that involves, on the one hand, companies and workers (operators, warehouse managers, transport distributors, etc.); and on the other, physical and technological infrastructure: cold rooms, industrial freezers, adapted vehicles, refrigerated displays, among others.

Foods considered perishable – vegetables, fruits, meat, fish and shellfish – require certain temperatures to preserve the nutrients they provide and their organoleptic properties. But they also require it to prevent decomposition and deterioration. Logically, if this happens, they would no longer be fit for consumption. And to better understand the importance of ensuring the correct refrigeration or freezing in which these products should be kept, we must know what happens to them if they do not follow a cold chain.

How does food deteriorate in the absence of an adequate cold chain?

Specifically, there are three forms of deterioration that damage and make it impossible to consume food products:

Microbial

Microbes are present in all natural environments: soil, air and water. In fact, foods of terrestrial origin contain microorganisms typical of their environment. However, most of the pathogens that cause disease in humans come from the soil. For example, root vegetables, tubers, and fruits can be contaminated on the farm by contact with dust, insects, and other elements. Even the water used for irrigation and handling by agricultural workers, during and after the harvest, without the required hygiene measures, are also sources of contamination.

On the other hand, seafood is contaminated with pathogens during handling by fishermen. As in ships, in landing centers, during transport and even in processing plants.

Furthermore, saprophytic microorganisms that biodegrade meat are present in the organism of animals during their life. They feed at the expense of these without harming them and begin to degrade it immediately after their sacrifice.

In summary, there are three types of bacteria:

  • Thermophiles, which can withstand high temperatures, such as Clostridium botulinum and Listeria monocytogenes.
  • Mesophiles, reproduce and survive at ambient temperatures between 30 and 40ºC. Much of the disease-causing bacteria fall into this classification. Its metabolism and multiplication is greater as the temperature rises, which accelerates the deterioration of the product. On average, these microbes can reproduce every four minutes. To stop its multiplication, it is necessary to keep the genus in a cold chain at -12ºC.
  • Cryophilic or psychrophilic, which resist and can reproduce even at subzero temperatures. Although their pathogenesis is not very relevant, they can make a food inedible after a long time at an inappropriate temperature.

Enzyme deterioration

Certainly, animals, vegetables and fruits have their own enzymes. These are essential for their digestive and metabolic processes while they live. After death, enzymes begin to digest their own tissues, breaking down proteins, carbohydrates, and fats. This deteriorates the product. Like the microbial ones, enzymatic reactions are directly proportional to environmental temperatures. In other words, by lowering the temperature through the cold chain, enzyme deterioration is slowed by 90% at -18ºC. And it totally stops at less than -60ºC.

Oxidative

To understand this type of deterioration, we must remember that all products of plant or animal origin have a certain percentage of fats and oils. It is what in Chemistry we know as triglycerides: 3 molecules of fatty acids combined with 1 molecule of glycerol, which are somewhat unstable by nature. The truth is that these triglycerides continue to break down at high temperatures, releasing glycerol and fatty acids, which reach higher levels at cooking and frying temperatures. Broken the link, they become free fatty acids that react with oxygen in the air and become peroxides and other compounds. The latter produce nutritional losses, unpleasant flavors and rancidity. They are also not healthy.

Similarly, vegetables and fruits contain other essential compounds for human nutrition and health:

  • Terpenoids, are aromatic compounds present in a large number of plant species.
  • Flavonoids. These nutrients are largely responsible for the intense colours of fruits and vegetables.
  • Chlorophyll and Carotenes, give flavour, aroma and colour to fruits and vegetables.

All these substances also oxidize and make the food unfit for consumption.

Importance of refrigeration and freezing in the cold chain

Indeed, the three classes of deterioration explained are directly or indirectly related to inadequate temperatures and the absence of a cold chain. To stop or counteract these effects, during the storage, pre-processing, processing and transportation stages, the mentioned products must maintain a cold chain.

In particular, most animal products will be better preserved at 0ºC or 0 to 4ºC to facilitate processing. While products of plant origin will retain their properties at about 10ºC.

On the other hand, cold chain requirements are different between types of meat, fish and shellfish, and plant-based products. In the former, the decomposition process begins when the animal dies. On the contrary, the latter are still alive after being harvested. They breathe, perspire and use their own energy to stay alive. Consequently, their storage temperature must be different, because they require a more humid and windy environment to facilitate the named functions and prevent them from losing biological water through transpiration. With the specified 10ºC, it is possible to reduce breathing and perspiration, ensuring that fruits and vegetables remain fresh and juicy.

Refrigeration and freezing

In conclusion, the cold chain can be carried out by two methods: refrigeration and freezing. In the first, food preservation is achieved at a low temperature, but without reaching degrees of freezing below 0ºC. This range of 0 to 10ºC that we have mentioned is the most common for fresh foods since the microbial process in it is very slow.

Unlike freezing, which consists of lowering the temperature for conservation below 0Cº. Although each type of food that requires this method has its particularities and its ideal degrees of freezing, most are stored at temperatures between -18 and -35Cº. Both the product and the water it contains freeze, which prevents the reproduction of bacteria. Apart from that, it makes the crystals formed in the cells small and round, so they will not break their walls. This will preserve their flavor and texture.

What happens if the cold chain is broken?

As you can see, the cold chain is so important in the quality of food that if it breaks in any of the stages of the product’s journey, it must be discarded. Because even by refreezing it, it has already been damaged and end consumers are exposed to a very high risk of food poisoning. So this would not be only in the loss of nutrients and substantial changes in texture and flavour.

To avoid breaking the cold chain, constant monitoring of temperature is essential at all stages of the product. From storage, through pre-processing, processing and transportation, to display at the point of sale. Therefore, temperature analysis and correction devices are essential in cold rooms, transport trucks, displays and cold trays.

Intersam helps you maintain the cold chain

At Intersam we have been manufacturers of customized industrial and commercial refrigeration systems and equipment since 1995. For this reason, we can design the solutions that your food processing, distribution, transport or marketing company needs to maintain the appropriate temperature of your products.

Our air-water, water-air and air-refrigerant refrigeration and air conditioning systems are highly efficient and have the most advanced technology applied in this sector. We serve your project anywhere in Spain and the world where you are. Contact us and we will help you maintain the cold chain!