4. La conservación y comercialización de los alimentos

BIOGEOSPHERE Bilingual Biology and Geology I.E.S. "J.S.Elcano (Sanlúcar Bda.)

Unit 2: Food and nutrition 1 2 3 4 5

4. Food preservation and marketing

Foods are made up of organic molecules which decompose in time and make them inedible. For this reason, if foods are not going to be consumed quickly they are preserved. Food preservation makes it easier to store and to market foods.

Food preservation is the process of treating and handling food to stop the loss of quality, edibility or nutritive value caused or accelerated by micro-organisms.

One of the main principles behind food preservation is to stop food decomposing. Decomposition is caused by:

- the action of enzymes in the food which can change the product.

- the multiplication of micro-organisms, which make the food decompose

and can produce toxic substances that then enter the food.

You should never eat rotten food; the organoleptic properties as well as the nutrients will have changed.

4.1. Preservation food methods

The main methods of preserving food are: cold, heat, drying, vacuum packing, irradiation, fermentation, smoking and the use of preservatives.

a) Cold

This is a very effective way of preserving food. Low temperatures reduce the speed at which micro-organisms reproduce and the action of enzymes.

There are three types:

- Refrigeration. The temperature is maintained a few degrees above O°C.

- Freezing. The temperature is below O °C and reaches -18°C.

- Deep freezing. The temperature varies between - 35°C and -150°C.

b) Heat

Heat destroys enzymes and kills micro-organisms.

Depending on the intensity, there are three different methods:

- Sterilisation. This gets rid of all the micro-organisms;

the food is subjected to temperatures between 110°C

and 120°C.

- UHT (ultra high temperature). Food is heated

to a very high temperature (135°C) for a few seconds.

This destroys all the micro-organisms but not the

nutrients.

- Pasteurisation. This applies a temperature of 72 °C

for 15 seconds followed by a rapid cooling down.

This kills the microorganisms but does not change

the organoleptic properties of the food.

c) Drying

This process involves eliminating the

water in foods to stop or delay

decomposition. Freeze-drying is

a commonly used method: a food is

frozen and then thawed

by high-pressure sublimation.

d) Vacuum packing

This system removes the air and therefore the oxygen so that aerobic micro-organisms cannot survive and many enzyme reactions cannot take place.

e) Fermentation

Some foods can change because of the action

of specific microorganisms through fermentation.

In contrast, other products can be preserved

better and can acquire new nutritional qualities.

Examples are cheese and yoghurt.

f) Smoking

Wood smoke contains substances that kill micro-organisms and stop food deteriorating, mainly because of the reduction in the quantity of water which occurs during the process.

g) Additives

Additives are natural or artificial chemical products that are added to food for different purposes. Here are some examples:

Additives	Function
Preservatives	Prolong the life of food, prevent it from spoiling.
Colourings	Make food look more attractive for the consumer.
Flavour enhancers	Improve the flavour of food.
Stabilisers	Maintain the texture of food and how it looks.
Antioxidants	Prevent oxidative changes in food.
Sweeteners	Give food a sweet taste; they may be sugars or artificial sweeteners; the latter are used in diet food and drinks because they have no calories.

Most part is chemical substances which have only modern use, but others, such as natural preservatives are used since the antiquity.

- Sugar and salt in food help to preserve it because of the loss of water inside the micro-organisms.

- Vinegar and spices are also good for preserving food because they stop the spread of micro-organism.

- Olive oil preserves food from the contact with the air and avoids putrefaction and contamination by micro-organisms.

We still don't know what effects many artificial food additives can have on our bodies. According to some scientists, excessive or indiscriminate use of certain additives can damage your health.

4.2. Food labelling

Consumers have a right to know certain information about the foods they buy. Food companies are obliged by law to inform us about their products on the label. The label is a guarantee of safety and must contain, at least, the following information:

- The name of the product.

- Net content: it is the quantity of the product (its weight or volume)

- The ingredients and their amounts in decreasing order by weight or volume

and additives.

- Instructions for use, if necessary and for preservation once open.

- Nutritional information (kind and quantity of each one)

- How to store it.

- Best-before date: manufacturers guarantee the product until this date;

or expiration date (if the food is perishable): after this date it could be

dangerous to eat the food.

- Name of the company and its address.

4.3. Food hygiene

Before food reaches the consumer it usually goes through a series of processes. These processes are collectively known as the food chain.

They are as follows: production, storage, transport, the industrial chain and marketing. All of these stages must comply with a series of hygiene procedures.

To avoid micro-organisms developing in foodstuffs all of the processes must be clean and hygienic. It is important that people working in this environment do not have infectious diseases and that their own personal hygiene is good. They must make sure that food products do not come into contact with animals.

The law establishes hygiene regulations for people handling food, company liability and monitoring procedures to ensure these regulations are followed.