Ultrapasteurization, also known as UHT (Ultra High Temperature), is a thermal process that rapidly heats a liquid (such as milk, juice or even beer) to very high temperatures — usually between 135°C and 150°C — for a very short time, 2 to 5 seconds.
Objective:
To eliminate all pathogenic microorganisms and most spoilage microorganisms, without significantly altering the flavor or nutrients. UHT is used to make products microbiologically stable, with a shelf life of months, without the need for refrigeration, while maintaining flavor and nutritional value as close as possible to natural ones.
Examples of UHT products:
- Long-life milk
- Cream in a carton
- Juice in a carton
Applications in Industries:
- Dairy products (milk, cream, condensed milk).
- Juice and tea industries (100% juices, nectars, ready-to-drink teas).
- Plant-based beverage industries (soy milk, oat milk, almond milk).
- Food industry in general:
Liquid soups;
Sauces (e.g.: bechamel, tomato sauce);
Ready-made broths;
Culinary creams;
Pasteurized liquid eggs, among others.
There are four main types of UHT (Ultra High Temperature) treatment systems, which vary according to the heating method and the type of product processed:
- Indirect UHT:
In this system, heating is done by indirect heat exchange, that is, the product does not come into direct contact with the steam. Heat exchangers, such as plates or tubes, are used to gradually heat the liquid to 135–145°C. The exposure time is approximately 20 to 30 seconds. It is ideal for products such as regular milk, juices and sauces, as it is more economical and simple, although it causes slightly more sensory alteration.
- Direct UHT by Steam Injection:
In this method, pure steam is injected directly into the liquid. This heats the product almost instantly. The exposure to heat is very short, 2 to 5 seconds, which reduces the impact on taste and color. It is used in products such as milk, plant-based drinks and delicate dairy products. After injection, excess steam is removed in a vacuum chamber.
- Direct UHT by Steam Infusion:
Here, the liquid is sprayed as fine droplets into a steam-filled chamber, which allows for ultra-fast heating — between 0.1 and 0.5 seconds. This technique offers excellent preservation of flavor and nutrients. It is ideal for premium milks, delicate juices and high-quality beverages.
- UHT VTIS (Vacuum Time Infusion System):
This is an advanced type of direct infusion, where the product is heated with steam in a special chamber and then immediately cooled in a vacuum chamber. Exposure to heat is extremely brief, usually between 0.1 and 0.2 seconds, preserving color, flavor and nutrients in a superior way. It is recommended for special milk (such as A2), ready-made teas, sensitive juices and functional beverages. This system is more complex and used in applications with higher added value. |
