Pasteurization is a basic method in food processing to prolong the shelf-life of a certain product. Pasteurization meaning, it is a process that eliminates bacteria with the use of heat. During pasteurization nutrients found in foods are preserved while keeping it safe to eat. The pasteurization process was discovered in 1862 by a great scientist named Louis Pasteur. According to Pasteur, the heating process in foods kills harmful pathogens and prevents spoilage in food. He develops the pasteurization process in milk and wine to prevent the sourness and rancidity. Pasteurized milk is the most common product that uses the pasteurization process. Aside from milk, other products are being pasteurized such as honey and wines.
There are many types of pasteurization used in food processing. Thermalization is where the milk is being heated between 57 degrees Celsius to 63 degrees Celsius for 15 minutes. It targets only the pathogenic bacteria in the milk and leaves the good bacteria. It uses a low temperature to avoid affecting the structure and taste of the milk. Batch pasteurization or also called low-temperature long time (LTLT) is a process wherein milk is being heated at 63 degrees Celcius for 30 minutes. However, long heating will surely affect the structure and taste of milk. Flash pasteurization or also known as high-temperature short time (HTST) is a process that uses high temperatures for a shorter time. The milk is being heated between 72 degrees Celsius to 74 degrees Celsius for only 15 to 20 seconds. Ultra-high Temperature (UHT) is like the flash pasteurization that uses high temperatures in a shorter time, but the temperature and time needs in this process are lower and shorter. In this process, milk is being heated between 135 degrees Celsius to 140 degrees Celsius for only 2-4 seconds.
1. Clarification
To ensure the safety of a product such as pasteurized milk, removing foreign matter from the product is very important. It uses a strainer to strain and removes the large solid particles and a centrifugal clarifier is being used to remove all soil and sediment from the milk. It is recommended to clean and filter the milk regularly to avoid the growth of bacteria.
2. Standardization
Pasteurized meaning, standardization of process of a certain product especially in milk is very important. To produce a safe and quality milk standardization of milk fat is needed to ensure the consistent quality of the product in the market. Consumers have different preferences in terms of milk.
Some of the consumers love skim milk which is low-fat milk while others prefer standardized milk with high-fat milk.
3. Homogenization
In this stage of pasteurization, this is where the milk fat globules are break down into tiny droplets. Homogenization discourages cream separation. There is an equipment used in this stage called milk homogenizer, it is working at between 100 to 170 bars to split all the fat globules into a tiny droplet to increase the level of integration of the fat. This is why the fat in the milk is uniformly distributed.
4. Heating
This is the most critical stage in pasteurization. There are different types of the heating process that you can use. However, it depends on the requirements of the product. The temperature of the milk should reach about 60 degrees Celsius up to required temperature which is 72 degrees Celsius to kill specific bacteria called Clostridium botulinum to ensure the safety of the product. There is a temperature check after the heating process to make sure that the required temperature is met. In case the temperature failed to reach the desired amount then milk must undergo the same heating process again.
5. Chilling
Chilling is not a pasteurization process, but it is a very important step in pasteurization. If you’re doing pasteurization especially in a large volume of milk, it is recommended to leave milk at ambient temperature. It is vital to subject it to the chilling process inside a blast freezer and reach a temperature that is between 2 to 5 degrees Celsius. In an ambient temperature, bacterial growth will happen and leads to spoilage of milk. Unlike chilling, low temperatures prevent the growth of harmful microorganisms.
