Milk and dairy products are nutrient-rich foods that provide essential vitamins such as vitamins A and D, as well as minerals like calcium. However, they are delicate foods that require proper refrigeration throughout the entire supply chain, starting from the collection of freshly milked raw milk, through the necessary processes for each specific product, to transportation and sale in stores. This is why refrigeration in the dairy sector is a crucial aspect to prevent deterioration and loss of properties in both the raw material and all preparations that use milk as a basic ingredient.
Essential aspects of milk and refrigeration in the dairy sector
In principle, milk obtained from a healthy udder is almost sterile. In fact, it contains natural inhibitors such as lactoferrin and lactoperoxidase, which prevent a significant increase in the bacterial count within the first three to four hours after milking at room temperature. However, cooling the milk to 4°C during this period preserves its original quality. This is the most commonly employed procedure to ensure the good quality of the product for both processing and consumption. Mechanical refrigeration and immersion in refrigerated tanks are the most commonly used methods for this cooling process.
Subsequently, milk goes through various distinct processes on its journey from the farm to the display cases and refrigerated cabinets of retailers and, from there, to our home refrigerators. At each stage, specialized refrigeration solutions are indispensable to meet strict tolerances. If the cold chain is broken with more than a one-degree variation, the products are at risk of spoiling.
From this perspective, refrigeration in the dairy sector involves developing a series of activities and having essential resources that vary significantly at each step. Therefore, it is crucial for the personnel responsible for the program at each stage to have a thorough understanding and strictly apply the fundamentals of operations. They must also have a comprehensive knowledge of the functioning of the equipment and components used to preserve the products. Otherwise, having cutting-edge technology to maintain the cold chain would be futile.
End-to-end refrigeration in the dairy sector
At this point, it is worth noting that the production of dairy products requires a complex process, regardless of their type. For example, processing milk for drinking is not the same as producing cheese, as cheese requires an even more meticulous process. Nevertheless, all dairy products must meet the condition of being safe for consumption. This is because such processes involve a high proliferation of microorganisms. Ultimately, what refrigeration in the dairy sector ensures is the coverage of the required cold chain at each step of the various processes.
As mentioned, refrigeration of dairy products involves several stages that are important to remember:
Collection and preparation of milk
Firstly, the processing company collects milk from local farms for further transformation into specific products. Nowadays, this step involves meeting more stringent requirements because the distances between the livestock establishments and processing plants are longer than before. These distances are often covered over several hours. For this purpose, tanker trucks have stainless steel bodies that improve insulation. The drivers of these vehicles must be familiar with the characteristics of their cargo and interpret the data from the monitoring equipment of the refrigeration system.
Pasteurization: a challenge for refrigeration in the dairy sector
Specifically, the pasteurization of milk is a process that ensures the safety we mentioned earlier. However, its usefulness goes beyond that because it also serves to alter some properties of the substance, such as achieving the desired texture for yogurt.
Pasteurization involves subjecting a product, in this case, milk, to a rapid thermal shock. Firstly, it undergoes a high-temperature treatment to eliminate pathogenic bacteria and minimize microbial activity.
Immediately after, it goes through the actual thermal shock in stainless steel compartments, usually sealed, where it receives a blast of cold through a compressor. In this case, the purpose of the mentioned cooling phase is to preserve the milk in a controlled environment where, depending on the type of product to be processed, it will have specific requirements. However, its essential function is to keep microbial activity as low as possible to prolong the shelf life of the product under optimal conditions.
Once pasteurization is completed, it is necessary to store the products at a temperature not exceeding 12°C, depending on the specific dairy derivative. In particular, drinking milk requires a maximum temperature of 6°C, which demands speed in the production chain after packaging.
As its name suggests, this process involves the separation of cream from whole milk. Through this process, skim milk is obtained, which needs to be refrigerated at around 4°C. This step is crucial in the continuous production of dairy products. By refrigerating the skim milk, the raw materials will maintain their properties and ensure their safety without experiencing any loss.
On the other hand, maturation is the transformation applied to certain foods to alter their properties, particularly texture, flavor, and hardness. In the case of dairy products, this process is used to produce cheeses that need to be stored in controlled environments at specific temperatures and humidity levels. These storage parameters facilitate the development of each cheese’s characteristic properties.
To be more specific, the average conditions for maturation processes are a temperature between 9 and 11°C, with a relative humidity of 85 to 95%. In some cases, these conditions may vary. Here is a classification of cheese types based on their maturation time:
- Fresh cheeses, with a maturation time of less than 30 days.
- Semi-cured cheeses require 1 to 3 months of maturation.
- Aged cheeses, need 3 to 6 months to mature.
- Vintage cheeses, with a maturation period of 6 to 9 months.
- Extra-aged cheeses are named so because their maturation process can exceed 9 months.
Regardless of the maturation time, at the end of the process, cheeses should be refrigerated at around 4°C to prolong their optimal conditions for consumption and, at the same time, halt the maturation process.
Once the industrial process is completed, the products move on to the distribution stage. They are loaded onto refrigerated trucks to prevent decomposition from starting.
For specific products like yogurt and certain cheeses, the conditions may vary as they require the preservation of certain types of bacteria that provide nutrients. It’s important to note that these preparations need a period of two hours at temperatures between 25 to 30 degrees Celsius after their production.
Returning to the trucks that transport dairy products, their containers must maintain a consistent temperature. Once again, we must emphasize the importance of training operators in the proper management of refrigerated transport vehicles.
Arrangement in stores
Indeed, refrigerators in supermarkets and retail stores need to maintain the temperatures required for each product. As a result, you will often find a distribution of dairy refrigerators in different areas of such establishments. For example, milk, cream, and yogurt are typically stored in sealed refrigerators. Cheeses are usually displayed in chilled display cases, while ice creams are kept in freezers.
We provide everything necessary for refrigeration in the dairy sector
Does your company intervene in any of the stages of dairy product processing? At Intersam, we provide the necessary refrigeration solutions for all stages of refrigeration in the dairy sector. Since 1995, we have been designing and developing refrigeration and air conditioning systems for industry and commerce. Our products feature the most advanced technology to ensure maximum efficiency and energy savings. Moreover, we serve your project anywhere in Spain and the world.