Why do we process food?

To make it edible so that we can eat it

To make it last longer by preserving it

To improve nutrient value by fermenting the food

edible

preserve

ferment

To Make it Edible

The wheat grains get ground up in a mill to make flour.

The flour is mixed with other ingredients such as yeast and water.

The mixture is baked in the oven to make it edible.

The natural source of flour is wheat.

Wheat grains are removed from the wheat plant.

Almost all food you buy in a packet, box, can, or container is processed in some way. Some natural foods cannot be eaten directly from nature. e.g. wheat

To Make it Edible

• Chicken, fish, and most meat must be cooked before you can eat it.

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• Fish needs some preparation to remove scales and bones before it can be eaten.

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• Chicken also undergoes processing as we don’t eat chickens with their feathers. Raw chicken is very dangerous to eat.

To Last Longer

We preserve food to prevent it from being wasted, polluted, or spoilt.

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Food preservation is the process of treating and handling food in such a way as to stop or slow down spoilage or prevent food born illnesses. Food is spoiled when microorganisms change it.

There are five basic techniques that make food last longer:

 Microorganisms are killed or prevented from multiplying,

The contact of the microorganisms with the food is removed, and new contact is made more difficult or impossible.

Microorganisms need certain basics to survive. Removing these will kill the microorganism.

One of the ingredients of the food is highly concentrated, so microorganisms cannot use it.

Certain additives prevent or slow down the growth of microorganisms.

To Last Longer

Below is an example of an apple that was not preserved, and one that was:

Natural Source

Not preserved

Preserved

To Improve the Nutrient Value�(e.g. fermentation)

Fermentation is when good bacteria is added to food. A lot of vitamins and mineral are released during this process. For example:

Adding yeast to make dough rise

The souring of milk to make yoghurt

Methods of Processing Food

Cooking

Pickling

Freezing

Fermentation

Drying and Salting

Cooking preserves food and stops it from going bad. The heat kills the bacteria.

Pickling involves putting food into vinegar or salt. This is called brine. The pickling fluid prevents bacteria from growing. e.g. pickled gherkins.

Freezing food slows down the growth of bacteria that can lead to spoilage and possible illness.

Fermenting is when good bacteria is added to food to change its state. e.g. yoghurt or cheese.

Drying and salting meat is when we cover it in salt and hang it up to dry. The salt draws out all the moisture from the meat and protects it against bacteria. e.g. biltong.

Advantages of Processing Food

Some food is pre-cooked or fully cooked, which saves time.

Seasonal food is available all year round.

Food lasts longer.

We can eat food that was harvested in another country.

Disadvantages of Processing Food

Too many additives may be toxic.

The flavour can change.

Nutrients can be lost. e.g. Cooking vegetables for too long destroys a lot of vitamins and minerals.

Disadvantages of Processing Food

There are dangerous additives in processed food that make it very bad for us:

Preservatives

Artificial Colourings

Artificial Flavourings

Only additives that have been proven to be safe for humans to eat or drink may be added to food.

Preservatives such as sulphur dioxide, are added to food to make it last longer. These are not always very healthy.

Artificial Colourings are added to food to make it look more attractive to consumers. Nowadays, natural colourants made from berries or plants, for example, are more widely used.

Artificial flavourings like sweeteners and salt are not very healthy and can cause organ and brain damage.