Ultra-high-temperature processing

[4] The heat used during the UHT process can cause Maillard browning and change the taste and smell of dairy products.

[14] After heating, the hot product is passed to a holding tube and then to a vacuum chamber, where it suddenly loses the temperature and vaporizes.

The process, referred to as flash cooling, reduces the risk of thermal damage, inactivates thermophilic microbes due to abruptly falling temperatures, removes some or all of the excess water obtained through the contact with steam, and removes some of the volatile compounds which negatively affect product quality.

Homogenization is a mechanical treatment which results in a reduction of the size, and an increase in the number and total surface area, of fat globules in the milk.

This reduces milk's tendency to form cream at the surface, and on contact with containers enhances its stability and makes it more palatable for consumers.

[17] In countries with a warmer climate such as Spain, UHT milk is preferred due to the high cost of refrigerated transportation and "inefficient cool cabinets".

[18] UHT is less popular in Northern Europe and Scandinavia, particularly in Denmark, Finland, Norway, Sweden, the United Kingdom and Ireland.

One study reduced the thiol content by immobilizing sulfhydryl oxidase in UHT-heated skim milk and reported, after enzymatic oxidation, an improved flavor.

[5] Two US authors prior to heating added the flavonoid compound epicatechin to the milk, and reported a partial reduction of thermally generated aromas.