Permeate - everything you need to know about milk standardisation

Milk is a highly nutritious, safe and natural food. Consumers today can choose from a wide array of different products including no fat, low fat or calcium enriched milk.

Whole milk is made up of milk fat, protein, milk sugar (lactose), water, vitamins and minerals (including calcium). It is a highly nutritious and quality product, naturally containing over 10 essential nutrients for good health and wellbeing.

The taste of milk generally depends on the levels of fat and protein in particular products.

From the farm to your glass

One process some manufacturers use to produce a variety of dairy products is ultra-filtration.

In this process milk is put through a very fine filter to separate the lactose, minerals and vitamins from the water and protein. The milk-sugar (lactose), vitamins and minerals which filter through are given the term permeate and are a valuable part of fresh milk.

The use of such technologies ensures every component in milk is used efficiently to maximise the yield of milk with no waste and produces a consistent product to the consumer throughout the year.

Permeate is a technical term which applies to all membrane filtration processes used across food production and other industries. For example when producing apple juice the fruit is put through a similar filtration process where permeate is the clear juice we end up buying and consuming.

Because milk is a natural food that comes straight from the cow, its composition can vary weekly/monthly due to the phase of the lactation cycle, what farm it is from and by the breed of cow. Regional and seasonal factors also contribute to differences in milk composition such as the fat and protein levels.

Processors review the composition of milk when it is delivered to them and standardise the components in milk to ensure consumers know they will receive the same quality product every time they purchase milk.

Use of the ultra-filtration process is one way of standardising the protein to a constant value throughout the year. Most countries of the world have standards that allow the fat and protein of milk to be standardised.

Standardising fresh milk

Most dairy manufacturers standardise the fat and some may standardise protein levels of the milk collected to meet consumers’ expectations of a consistent product all year round. Using a collection of natural milk components (permeate) separated by ultra-filtration, is one way to standardise protein. Some other ways include adding/removing fat.

Government regulations ensure that milk products conform to food standards for quality, consistency and food safety. The composition of milk is governed by the Food Standards Australia New Zealand (FSANZ) Food Standards Code (the Code). These standards are consistent with international standards – milk consumed in nearly all developed countries will have very similar standards.


The Code allows manufacturers to add or withdraw milk components to standardise the composition of milk sourced from dairy farms, as required, to produce nutritionally consistent and safe products.

Under the Code, the standard for packaged whole milk requires that it contain at least 32 g/kg (3.2%) of fat and 30 g/kg (3.0%) of protein.

By and large, consumers want to know that every time they purchase fresh milk it will have a consistent composition and taste. Standardising milk gives consumers this consistency.