Demand for so-called functional milks (milks fortified with extra vitamins and minerals) has increased as the desire for full-cream milk has dropped off. Milk manufacturer National Foods reports sales of full-cream milk have dropped by nearly 25% during the past 20 years.

Ever wondered how your milk became enriched with extra calcium or Omega-3 fatty acids? Perhaps you have questioned how low-fat milk is just that – low fat? Food Investigators has had a look at the science of milk.


The Science of Milk

Once milk has arrived at the factory – it goes through a complex production process - before it is turned around and distributed to milk depots, supermarkets and cafes. The production process takes just a few hours. The aim is to make sure that each litre of milk you buy – regardless of type – tastes the same each time you buy it.

This is how it is done: Milk fat or cream is separated from the skim milk. Skim milk is pasteurised, cooled and stored. Fat is broken down into homogenous globules to prevent it from rising to the top. For milks with extra protein – lactose is removed from skim milk resulting in a concentration of protein. Various components are added together depending on the milk type.

For example, regular milk combines skim milk with 3-4% fat. Different powders such as calcium, Vitamin A and Omega-3 are added to the milk to create the different varieties. Milk is packaged and distributed. Excess fat or cream is used in the manufacture of butter and cheese.


Milk's Nutrients

Milk contains a balance of protein, carbohydrate and fat as well as the following nutrients (depending on type of milk):

Skim Milk: The best rehydrator?

Researchers from the United Kingdom believe a drink of skim milk after exercise may promote faster recovery and rehydration than water or isotonic “sports” drinks. The Loughborough University’s School of Sports and Exercise Sciences conducted a trial involving 11 volunteers. They exercised until they lost 1.8% of their body weight before drinking either skim milk, skim milk with added sodium chloride, water or Powerade. Those who drank skim milk reported unchanged urine output in the five hours following the exercise session. Those volunteers who drank water or Powerade increased their urine output in the first two hours after finishing exercise. The researchers concluded skim milk is more effective at replacing sweat losses and maintaining hydration than plain water or so-called “sports” drinks.


How Much Fat?

Full cream milk contains 3-4% fat. Children under the age of 2 should drink full cream milk.

Reduced fat milk contains approximately 2% fat. Children over the age of 2 can drink reduced fat milk. SKIM milk contains less than 1% fat. Children should not drink skim milk before the age of 5. Did you know milk is mostly (approximately 87%) water?