Background:
Background: Milk forms an integral part of the human diet from the nutritional point of
view. Besides nutrition, it has also unique functional properties which are harnessed by the industry
for numerous uses. Being highly perishable specific techniques are required to minimize the losses
during processing and adequate preservation of this precious commodity. In the U.S. and many other
parts of the world, the traditional pasteurization of milk requires a minimum heat treatment of 72ºC
for 15 seconds with subsequent refrigeration. However, the advent of Ultra High Temperature (UHT)
treatment of milk has added a new dimension to the marketing of liquid milk in urban as well as remote
areas without the requirement of cold chain management. The distinctive feature of UHT processed
milk is that it is commercially-sterile-not pasteurized and so has long shelf life at room temperature.
UHT milk, also known as long-life milk, is emerging as an attractive commercial alternative
offering a hygienic product of unmatched quality, which can be bought anywhere, at any time
and in any quantity. The present review will discuss numerous aspects of UHT processing of milk
with reference to historical significance, fundamental principle, various systems used and prerequisites,
type of exchangers used, fouling and other defects in system, chemical and microbiological effect
of the treatment, its effect on nutritional components, organoleptic quality of milk and the advantage
and involved challenges of the process.
Conclusion:
Raw milk is easily contaminated with pathogens and microbes and hence its consumption
of raw milk is associated with certain ill health effects. Therefore, heating milk before consumption
is strongly suggested. Thus, UHT treatment of milk is done to ensure microbial safety and also
to extend the shelf life of this highly perishable commodity. Heating milk at such a high temperature
is often associated with the change of organoleptic properties like change in flavor or cooked flavor,
rancidity due to microbes or acid flavor, etc. But UHT treatment does not substantially decrease the
nutritional value or any other benefits of milk.
Research and development of ultra-high temperature delayed crosslinking acid system
