How Is Milk Pasteurised?

In the days before the Second World War, most milk was drunk straight from cows and was not treated by pastuerisation. This raw milk did carry a health risk in that infected milk could spread tuberculosis and many herds of dairy cattle were infected by TB.

The process of pasteurisation involves heating milk or yoghurt to 60 degrees Celsius to kill off most of the bacteria that are contained within it. Heating to this temperature, but no higher, does not change the proteins in the milk or the yoghurt so the taste is not really affected.

Sterilised milk – often called UHT milk – has been heated to 100 degrees Celsius to guarantee that all bacteria have been killed. However, this denatures some of the milk proteins and UHT milk has a strange taste that many people find unpleasant.

Today, most milk products are pasteurised in this country but some organic farms do produce raw milk and it is possible to drink it. Many experts do not recommend it though, as the storage facilities need to be extremely good to avoid the milk going off.

Pasturization is the act of flash heating and rapid cooling of whatever is being pasturized. This kills any unwanted bacteria,