What is pasteurised milk?

Almost all the varieties of milk that you get from shops, irrespective of the brand, are pasteurised. Pasteurised milk has been dominating since 1800s, because of the safety. Its role in extending the shelf life of milk is another factor in favour. Today’s classroom looks into the term, pasteurised milk.

What is pasteurisation?

Pasteurisation is the process of heating milk to a specific temperature for a particular period of time. In most milk processing plants, the milk is heated up to 161 degree Fahrenheit and rapidly cooled back to a 39 degree Fahrenheit. This process was developed by Louis Pasteur and was soon adapted in the dairy industry. Since then, except milk labelled ‘raw milk’ every other types of milk is pasteurised.

It can now last longer, between two to three weeks and two to three months, depending on the type of pasteurisation. Milk pasteurisation can be of various types such as UHT (Ultra Heat Treatment) and HTST (High Temperature Short Time). The UHT milk kills all forms of bacteria and need not be refrigerated. It lasts for about three months and can be consumed directly.

On the other hand, in HTST (common) type of pasteurisation, the milk has to be refrigerated and consumed within two to three weeks and kills only certain types of harmful bacteria.

However, it should be noted that milk pasteurisation is not intended to kill all the organisms in milk or change the quality or taste; it aims to reduce the disease causing pathogen and prolong its usage.

Why pasteurise milk?

As raw milk, at an ambient temperature, is prone to the growth of microbes and spoilage, pasteurisation of milk can help kill these harmful microbes responsible for the spread of diseases such as listeriosis, typhoid fever, diphtheria and brucellosis. At the same time, it reduces the bacterium that causes food spoilage. However, refrigerating milk is still important.

That said, there are constant debates over the consumption of pasteurised milk on the grounds of safety and health. Many argue that raw milk is healthier as the nutrients remain intact and pasteurised milk eliminates the original vitamins and proteins and lacks in quality. But the Food and Drug Administration (FDA) and CDC (Centres for Disease Control and Prevention) recommends pasteurised milk over raw milk as the exposure to harmful diseases are reduced.

As access to raw milk is anyway limited in urban areas, you are left with pasteurised milk as your only choice.