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November 20, 2018

If this is cream, what does the milk look like?

“Cream always rises to the top”. A good idea or person cannot be ignored forever. If you have ever had a cup of tea, added milk, the cream bit eventually rises to the top. Interestingly many people do not like the layer of cream that forms when taking tea and often spoon it out or try and stir it back into the tea so that the taste of the beverage is a smooth one.

The contradiction in that action is interesting because what gives milk and many other foods the taste we desire is the fatty part of it, in this case the cream. So we want it but we do not want to see ourselves taking it. The question is, should we then separate the cream? And if so how should we do it?

Milk is that white liquid produced by the mammary glands of mammals and is the primary food for their young ones. Humans are mammals and therefore have similar habits.

Until a baby is six months old, mother’s milk is adequate for all the baby’s nutritional needs. And even after six months, mother’s milk continues to be an important component of the infant’s diet.

But unlike other mammals, for humans this is not the only type of milk consumed. Other than the natural mother’s milk for babies, many humans continue to drink milk beyond childhood. This milk is primarily derived from cows, which produce around 85 per cent of the milk used by humans.

This idea of drinking other mammals’ milk is more than 10,000 years old having started with the agrarian revolution and the domestication of cows, sheep and goats.

The benefits of milk are many. Milk is mainly water, but has significant amounts of protein, fat, sugar, minerals and vitamins, almost all the major nutritional elements.

For example, milk protein contains all the essential amino acids necessary for building new tissues and repairing injured ones. Essential amino acids are ones that the human body cannot make on its own and so they have to be present in the diet. A glass of milk will provide about a quarter of the daily requirement for calcium, an essential mineral in maintaining strong bones, teeth and the smooth functioning of the heart.

Milk provides a similar proportion of riboflavin or Vitamin B12, which is important for the health of our nerves. The same glass of milk will provide about 10 per cent of our daily requirement of phosphorus needed by cells to generate energy; potassium, which is essential for the heart and maintaining proper levels of body fluids; and niacin, another vitamin, which is a component in many enzymes in the body. Whole milk also has about ten grams of sugar in the same glass.

 Perfect as it is, there are some problems with milk, the main one being everyone and everything knows that milk is so good. Humans have overcome the problem of cows behaving badly at their milk being taken away by breeding them to produce milk in excess of their needs.

The world record is a cow able to produce in excess of 12,000kg of milk a year. But there is still the problem of microorganisms, bacteria and parasites that find milk tasty especially if the milk is allowed to stand for long, which is the case when milk has to be transported from the farm to the kitchen.

Raw milk can be a serious health hazard. The common diseases include brucellosis, which is like tuberculosis, salmonella and E. coli, which cause dysentery.

The treatment to prevent these diseases in milk is pasteurization, heating the milk to a high temperature for a short period of time and then packaging it. This allows the milk to stay fresh for a few days.

But there is then another problem. Chemistry-wise milk is an emulsion, a suspension of fat in water. Oil and water as we know do not mix and so there is a tendency for the fat to separate out to the top. Bacteria and others know that in life the place to be is with the crème de la crème and it helps keep the milk longer if some of the fat is removed from the milk.

The rest of the milk is then homogenised, shaking and stirring the milk so that the fat particles are broken down into smaller particles that disperse throughout the milk and do not form the layer of cream on the surface.

And so commercially we are left with two products — milk which has been skimmed to some degree and cream. Heavy cream is about 40 per cent fat and 55 per cent water, is very rich in calories but has minimal protein and sugar compared to semi-skimmed milk at about three per cent fat.

 Because cream is so rich we can only take it in small quantities or add other things to it like sugar, eggs, air and cold to make ice-cream.

Even then there is a limit to how much we can take or we suffer the consequences. In the end, the best way to take advantage of the goodness of milk is to drink whole milk, pasteurised and homogenised so that it is safe and tasty. Cream does rise to the top, but it can be full of bacteria. Cream left on its own behaves badly.

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