Everything You Need To Know About Ultra High-Temperature Sterilization

Ultra high-temperature sterilization refers to sterilizing liquid food by heating the food to a temperature above 135 degrees. During the heating process, bacteria and germs get killed, leaving the food safe for consumption.

Microbial scientists use two primary ultra-high temperature sterilization methods – steam and gas. The more popular way is steam because it's easier to control when heating the liquid food and provides more consistent results than a gas treatment. 

What is UHT process equipment?

Ultra-high temperature (UHT) process equipment permanently sterilizes liquid food. The equipment is contained in steel, glass, or stainless steel chamber and filled with a gas or steam environment. The steam fills the chamber by circulating through multiple tube coils, while a gas fills the chamber from below the food level and then flows upwards through coils. Since UHT process equipment has several layers of long-term-stable locking covering for safety reasons, small leaks get easily sealed without causing any damage to the equipment.

Advantages of using UHT process equipment

The advantages of using UHT process equipment to sterilize liquid food are that it is fast, energy-efficient, and cost-effective. Since the process directly heats the food, there is no need to preheat the chamber or energy required to maintain a high temperature for an extended period. That results in enormous energy savings compared to other methods that require preheating. In addition, since it's a one-time process that only takes seconds, the equipment requires less maintenance than different types of sterilization methods.

Different processes performed using UHT equipment

1. Pasteurization

Pasteurization can be performed by using UHT process equipment for sterilization. In this process, boiled water helps heat the food to a temperature between 63 – 134 degrees. The heated liquid food is then stored in an insulated container until required. However, since pasteurization is often considered an "ultra-pasteurized" method, it's important to check product labels before purchasing.

2. Low and high acidic aseptic processing

Low acidic aseptic processing helps sterilize liquid foods formulated with reduced amounts of acid (for example, the manufacturer may prefer to sell the food in a less acidic form). The process uses steam to heat the food and cool it down quickly with cold water after the heating step.

The high acidic aseptic processing method is different from the low acidic because it involves using gas instead of steam for sterilization. The gas method has less risk of oxidation than the steam method. Therefore, the high acidic aseptic processing method is a better option for sterilizing liquid food with more acid.

3. Ultra-High Temperature (UHT) sterilization

The UHT process uses gas or steam to heat liquid food to a temperature above 135 degrees. The heated liquid food is then stored in an insulated container until required. The process is sometimes described as "ultra-pasteurized" because the food gets heated to temperatures above 250 degrees, but it does not have the same effect as pasteurization.

4. Indirect or direct thermal processing

In direct or indirect thermal processing, the milk used to make cheese and yogurt is sterilized via steam rather than using UHT process equipment to sterilize milk products.

Conclusion

The UHT process is one of the most cost-effective ways to sterilize liquid food. It's easy to set up and use and generally provides more consistent results than other methods.

A production manager must rely on an excellent supplier to ensure that the process equipment is working efficiently and maintained accurately. The supplier should be experienced in providing the best solutions for customers who need UHT process equipment, such as pasteurizers for dairy products or sterile equipment for the pharmaceutical industry.