Throughout human history, food preservation has been essential to survival.
Fresh or raw food is perishable, that is, it becomes unfit to eat over a relatively short time as a result of decay caused by the multiplication of living, microscopic organisms including bacteria, yeasts, moulds and enzymes. Some of these micro-organisms are harmful if eaten and cause food poisoning.
Since the earliest times, therefore, mankind has looked for ways to prevent foods from perishing whilst keeping them pleasant to eat.
Traditional methods of preserving foods include sun drying, salting, smoking, freezing and pickling. In the late 18th century, the French emperor Napoleon Bonaparte offered a prize to anyone who could come up with a new way to preserve food. Traditional methods of preserving food did not keep it edible for long enough to reach France’s far flung armies.
The prize was won by a confectioner named Nicolas Appert, who had discovered that heating food to high temperatures inside sealed glass jars stopped it from ‘going off’.
Soon after this it was discovered that the process worked as well with tinned iron canisters as with glass bottles - but these had the advantage of being lighter, easier to seal and less prone to damage during transportation and storage - and so the food can was born. The iron was coated with a fine layer of tin to stop it from rusting.
No one knew at first why Nicolas Appert’s process preserved food, but it meant that soldiers fighting a long way from home could be fed properly and that sailors too could have a healthier diet on long voyages. It was over half a century later that scientists discovered that the heat used in the canning process kills the micro-organisms which cause food to decay. Cans continued to be used mainly by the army and navy until the 1920s. The first cans were expensive, because they were made by hand and a good tinsmith could only manufacture six to ten a day. They were large, heavy and a hammer and chisel were needed to open them! But in spite of these drawbacks, their convenience was invaluable and unprecedented.
Gradually, the production of cans became mechanised. A machine was developed to stamp out the can bodies, then to solder the can ends. It was discovered that if the food was heated under pressure, the heating and cooling times necessary became significantly shorter. This improved the flavour, texture and nutritional value of the food. After the 1920s, canned food lost its military image and became fully accepted as part of the national diet. The industry continued steadily to progress and increase in efficiency.
The first automated production lines produced around six cans an hour. Today’s sophisticated production lines can produce in excess of 1,500 cans a minute.
The development of cans continues today. Research and development has led to the production of cans in all sorts of different shapes and sizes. Cans with easy-open-ends either with ring pull or peelable foil that don’t require a can opener and also bowl shaped cans which are microwaveable and so on. Today, cans weigh over 30% less than even just 20 years ago, take fewer raw materials to produce, but are stronger and safer than ever. The processing of food in cans also continues to develop to enable food manufacturers to fill cans faster and handle the latest styles of metal cans and ends.
The food can has been around for over 200 years and because it is such a safe, strong and convenient form of packaging, it is likely to be around for at least another 200 years!