The processing

The process of milk production has changed dramatically over the years. Long gone are the days when farmers completed all tasks by hand; now machines, online technology and automation have streamlined the process and made it more efficient. 

These are the basic steps from cow to carton:

• From cow to factory

Today cows are milked using vacuum cups which are attached to the cow's teats. The milk is transported through stainless steel pipes to large, refrigerated vats and then stored at 5 °C or less. Within 48 hours, milk is taken in tankers to a milk factory where it's pasteurised and homogenised.

• Pasteurisation

The next step in the process is pasteurisation. This milk is heated to 72 °C for no less than 15 seconds, then immediately cooled to destroy any harmful bacteria and micro-organisms. This technique helps to extend the shelf life of the milk.

• Homogenisation

Homogenisation helps to evenly disperse fat globules. Milk is put under pressure through fine nozzles, which stops the cream separating and rising to the top. This allows manufacturers to obtain consistent texture and taste.

This process allows for greater consistency of milk and milk composition that can be adjusted for year-round consistency. Milk composition is standardised so elements like fat content are made consistent no matter the season or breed of cow the milk comes from.

• Centrifugal separation

This process removes some or all of the cream to make reduced-fat, low-fat or skim milk. Skim milk solids can be added back to improve the taste and texture and increase nutrients like protein and calcium.

• Permeate

In order to standardise milk year-round, some manufacturers use a process called ultrafiltration where a membrane filter separates certain elements from milk. Milk is passed through a very fine filter, and the lactose (milk sugar), vitamins and minerals that filter through are referred to as ‘permeate’.

In milk processing, the word ‘permeate’ does not refer to anything added which was not already part of milk.

• Further Processing:

This step may involve micro-filtration, increasing the storage life by ultra-high temperature (UHT) treatment, and mixing or culturing milk for flavoured and yoghurt products.

• Packaging:

The milk travels through pipes to the automatic packaging machines that fill and seal the milk into paper cartons or plastic jugs. As the containers move through the assembly line, a date is printed on each of them to show how long the milk will stay fresh.

It is amazing to consider how the site has transformed, from the days when milk was delivered by individual farmers on horse and cart, to the industrial process it is today.