What is the difference between UHT and Pasteurised milk?!
Pasteurised is only heated for a short period to kill the most dangerous of bacteria (pathogens), but it does not kill all those, which whilst harmless in the quantities present, will cause the milk to spoil after a few days. UHT is heated to a higher temperature and for longer to kill more bacteria and the milk will last much longer as long as the container is not opened. It does have a slightly different flavour which some may not like, but if you don't mind it is a good way to buy all the milk you need in one go, for instance if you live some distance from the shops or in winter, if bad weather is likely to housebind you for some days or there is likely to be a shortage in the shops. It is sold as 'longlife milk', and is available whole, semi-skimmed or skimmed, as is pasteurised.
It is also possible to completely sterilise milk, to make it keep even longer, but sterilised milk has a caramel like flavour which not all will like.
UHT is a type of pasteurization that uses ultra-high temperatures for a very quick period
the advantages is it can be stored sealed at room temperature for 6-9 months
regular pasteurized milk can't.
the drawback is the ultra-high temperature will destroy a few more of the nutrients and vitamins over standard pasteurization