Processing Methods

Pasteurisation ensures that dairy products are safe for us to eat and drink. The process involves heating milk to a significantly high level to destroy harmful bacteria and prolong shelf-life. Milk and dairy products undergo a number of safety, quality and sanitation procedures such as pasteurisation, making them among the most highly regulated and safest foods available.

Pasteurisation

Milk is a highly perishable product and can lose its desired qualities very easily. Milk left at room temperature will start to grow bacteria within two days. To prevent any undesirable bacteria from growing, milk must either be heated to destroy them, or cooled to slow down bacterial action. This is the process of pasteurisation.

The milk is heated to 70 – 75 degrees centigrade and then rapidly chilled again to 4 degrees. The heat destroys most bacteria and the rapid cooling process prevents the remaining bacteria from multiplying. It also destroys any organisms (bacteria or viruses) that could cause illness. Pasteurisation has practically no effect on the taste or nutritional value of the milk.

Once pasteurized, milk and milk products are then routinely tested for product quality and safety. Most domestic fresh and soft cheeses are also pasteurised. Hard cheeses aged longer than 60 days do not require pasteurisation.

French doctor and scientist Louis Pasteur invented the process of pasteurisation more than a century ago. Since its discovery, pasteurisation has safeguarded much of our food supply, including milk and dairy products.

This is a form of pasturisation where the milk is subject to extremely high temperatures (140 degrees). This lasts for for 2-4 seconds. It is then immediately cooled. Almost all bacteria are destroyed in the process and the milk can be kept for months without refrigeration in its sealed packaging.

	Question: Why does UHT milk taste different to pasteurised fresh milk?
	Answer: The higher the heat treatment temperature the more of a “cooked” flavour develops in the milk and therefore the taste differences between the pasteurised and UHT milk. UHT milk usually has a more “cooked” flavour, which is slightly “sweeter” due to the higher heat treatment. Pasteurised milk still has a fresh milk taste.

Homogenisation

Milk is homogenised to ensure that fat globules are dispersed evenly through the milk. If you do not see a layer of cream at the top of a bottle of milk, this does not mean there is no cream in the milk. Because butterfat is lighter than the rest of the milk, it rises to the top and forms a layer of cream. To prevent this milk is homogenised. In the process the milk is forced through tiny holes under high pressure. This breaks the fat and distributes it evenly throughout the milk. Homogenised milk has a creamy taste and it whiter than before.

	Question: What is "sterilised" milk?
	Answer: Sterilised means the destruction of all forms of micro-organisms. Sterilised milk is homogenised milk, which has been filled in a bottle, sealed, and the product is exposed to steam at a temperature of about 120°C for about 20 minutes.