Milk - a natural product

Monday 29 June 2009 | From Dairy Australia

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.

Because milk is a natural food that comes straight from the cow, its composition can vary by farm and by breed. Regional and seasonal factors also contribute to differences in milk composition.

Government regulations ensure that milk and dairy 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).

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

To satisfy consumers’ demand for choice of products, manufacturers, in accordance with the Code, may vary the levels of milk-fat, milk sugar (lactose) and protein (see figure 1 - Milk process diagram).

Whole milk is made up of milk-fat, protein, milk-sugar (lactose), water, vitamins and minerals (including calcium).

In simple terms, permeate is milk that has been filtered through a very fine ‘sieve’ to separate the milk-sugar (lactose) and minerals from the milk protein.

Latest processing techniques enable manufacturers to use these various components in different combinations to produce versatile products demanded by consumers.

Food Standards Australia and New Zealand (FSANZ) regulations

Cows’ milk has regional and seasonal differences resulting in varying levels of fat and protein in the milk collected from farms.

Under the Food Standards Code, components of milk can be added to or withdrawn from milk to standardise natural variations in fat and protein and produce a range of consistent and nutritious products. Manufacturers produce a variety of milks to meet consumer demand consistent with the regulations.

The standardisation process may include the use of membrane separation technology, which produces one stream known as milk permeate, a part of normal milk containing lactose, vitamins and minerals, and a second stream that contains the protein and fat. The World Health Organisation body for food regulation, Codex Alimentarius, defines milk permeate as ‘… the product obtained by removing the milk proteins and fat from milk, partially skimmed milk or skimmed milk by ultra filtration'.

The standardised milk products need to conform with the national food regulations for milk (the Food Standards Code). For example, the standard for whole milk requires that milk be at least 32 grams per kilogram of fat and 30 grams per kilogram of protein; and skim milk be a maximum of 1.5 grams per kilogram of fat and a minimum of 30 grams per kilogram of protein. More information about Standard 2.5.1 - Milk

Key points

• Permeate is produced when milk is passed through a sieve (ultrafiltration) to separate the milk-sugar (lactose), vitamins and minerals components from milk protein. 
• Dairy Manufacturers may adjust these components to produce a variety of different types of milk (e.g. low fat, high calcium, no fat) to meet customer demands, consistent with the food regulations. 
• The composition of milk is governed by the Food Standards Australia New Zealand (FSANZ) Food Standards Code, which ensures consumers purchase nutritionally consistent, high quality and safe products. 
• The FSANZ Food Standards Code allows processors to adjust the components of milk delivered from farms, when necessary, to produce a wide variety of nutritionally consistent and safe products.
  

Figure 1 - Milk process diagram