Apart from their unquestionable usefulness, tinned food has already racked up quite a long history. With food in tins, we can feed and save people over long distances that have been stricken with disaster or confront humanitarian catastrophe. Where would our explorers, our soldiers and our round-the-world sailors have got to without them? But for most of us, they bring true salivation when we find that we have failed to top up the fridge and now it's dinnertime and the family is hungry.

Nowadays millions of people throughout the world eat food from tins.

Two countries, the United States and Canada, by themselves account for 37 billion of the tins of processed food manufactured yearly. About 1,500 different types of food products can be processed, so it's no wonder the market is a huge one. Of course, it would be quite a different story if we were not always in such a big rush, and have become used to having an easy alternative permanently available in the pantry; just open, heat and serve. In addition, families are smaller these days and their members more likely to be active outside the home, meaning that different mealtimes and different tastes have to be catered for, Tinned foods are a simple, eminently practical solution to the problem

But are they really bad for you?

No matter how many millions of people would be at a loss to feed themselves if their openers were taken away from them, nutritionists keep on telling us that the best tasting and healthiest food is whatever's fresh and in season, and which has undergone the least possible manipulation. Does that mean that tinned foods are low in nutritional value and may even have a negative effect on the organism? The answer is not necessarily. Just as with practically anything else, overdoing it is bad for you. Eating tinned food as part of a healthy, balanced diet need not be a bad thing, providing that certain special situations are taken into account.

Tinned fish and vegetables usually contain a high percentage of salt, and that means� people suffering from high blood pressure should go easy on them or skip them altogether. Many others are packed with sugar - tinned fruit in syrup, if an example is needed,�and vegetable fats, and this is something that weight-watchers and diabetics should bear in mind. In the event,�you should always read the label and get a clear idea of what other ingredients have been used in its preparation. Sodium, for instance, usually appears as sodium phosphate, a preservative.

A Long Way Back in the Kitchen
Tinned foods have been a part of our lives since the beginning of the 19th century. Over the years, techniques used in preserving and packing the food have been improving steadily� to allow the contents retain more of their flavour and nutritional properties. At the same time, the aim has been to see that they are even more resistant to contamination and spoilage. In the early 20th century, the foods were usually treated with some sort of heating process to kill off the microorganisms that cause spoilage. That usually worked well enough, but it also altered the composition and texture of the food and had a negative effect on its quality. To minimise that drawback, other processing methods have been introduced such as passing an electric current through the can, which acts like a microwave oven,� penetrating deeper into the food and usually reducing the time needed for the process, as well as preserving more of the original taste and texture.�

It's curious, though absolutely true, that some tinned foods actually give you more health-giving nutrients than they do in their raw form. For example, it is easier for the body to absorb the beta carotene in tinned carrots than from the raw kind, and peas that are processed immediately after picking will have more vitamin C than those that have spent several days at room temperature before they are eaten.

Preservatives and Anti-Oxidants
Tinned food usually will contain several different types of chemical additives that help preserve the flavour, colour and texture of the contents. These can be classified as colouring agents, preservatives, anti-oxidants to retard spoilage, and sweeteners. In the countries of the European Union, these additives are identified by a registry number, such as E-202,�rather than their chemical description.

The more you use of these additives, the greater their harmful effects will be. There's no question that certain long-term risks are involved, for example in nitrates and nitrites, which are commonly used antioxidants. But although their adverse effects are beyond question, they continue to be used because they are the only sure way of preventing the appearance of Clostridium botulinum, the bacteria that causes botulism.

A few simple precautions ought to be taken so that we can enjoy all the benefits of tinned goods without cause for concern. For example there's a risk that some of them may convey to the body some of the heavy metals used in manufacturing the container. It's best to avoid those that show soldering on the sides of the tin and look for the ones that have a protectiveprotective coating on its inner surface.� If� metal particles are visible in the contents of an oily food (such as tinned fish) or the colour or the smell seems a little off� it's wisest to toss it. And never, never eat from a bulging or swollen tin. This problem, which preserved pimentos are particularly susceptible to, is a telltale sign that botulism is present on the inside.
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