Packaging makes foods easy to store, handle and identify. It also helps protect them from spilling and from being damaged. In addition, special packaging materials and methods protect food from air, bacteria, chemicals, insects, light, moisture and odours - all of which might spoil the food.

Attractive packaging can also help promote the sales of food and advertise the product. Most food is packaged by machines into containers and packaging is the last step in the processing of food.

Packaging is chosen depending on the properties required. For example, eggs are packed in thick, sturdy cardboard or plastic cartons to protect them from breaking. Some foods such as coffee, jam and peanut butter are used a little. They are packed in cans or glass jars that have a re-sealable lid. Plastic bags and wrapping keep air from meat, bread, potato-crisps and many other foods.

One very useful function of packaging is the ability it can have to store or preserve food for long periods of time. This is particularly useful for active people who may not have the time to prepare full meals, so can just re-heat something from the larder, or travellers going away for long periods of time into unoccupied areas.

Food preservation is used to protect food from microbes and other agents that could spoil the food, so it can be consumed at some point in the future. The idea is that preserved food should have the same taste, smell, appearance and texture, whilst maintaining its nutritional value.

Canning food involves heating it then sealing it in an airtight container. This method was discovered in 1809, and replaced the original corked glass jars. Canning can also be a safe and economic way to preserve food at home.

There’s always been some kind of packaging used for preservation. When Stone Age man killed a wild animal and carried it home to his campfire to share with his family, he probably wrapped the meat in a skin or leaves to protect it from insects, the sun or the rain.

Since earliest times, people have stored away as much food as possible to last them through the winter, a harvest failure or some other crisis. Some of the earliest methods such as drying wheat in the sun and storing it away, smoking fish or storing meat in salt to make it last have been in existence for 2,000 years and are still used today. Glass blowing was developed around 1500 BC and bottles, jars and drinking vessels have been found in Roman sites. But in spite of people’s efforts to protect and preserve their food, meat still rotted and corn went mouldy. To disguise the horrid taste and smell, people used spices and herbs in their cooking.

In 1795, the armies of England, Prussia, Austria, Spain and Sardinia were fighting in France during the revolution. The French army was losing many lives, not just through battle, but also scurvy and malnutrition. Not enough food could be foraged, nor could be provided for soldier’s abroad or those at sea. The French director offered 12,000 Francs to anyone who could devise a new and successful method of preserving food for long periods.

Nicolas Appert was a cook and confectioner in Paris when he devised a method for heating foods and sealing them in glass bottles. He believed this process destroyed the substance, which he called ferment, which causes food to spoil. By 1809 his products received such recognition that he received Napoleon’s reward.

Appert wrote a book describing his method, ‘The Art of Preserving All Kinds of Animal and Vegetable Substances for Several Years’. By repeated tests, Appert demonstrated that heat, applied to food sealed in an airtight container, in some manner prevented the food from spoiling. He used wide-mouthed bottles, which he filled with the food, corked and heated in boiling water. He did not know why his methods were successful and many scientists disputed his theories. Appert’s factory was destroyed when France was invaded and he died in poverty. Nowadays many of Appert’s guidelines are followed such as complete cleanliness, which reduces the amount of spoilage organisms that will have to be killed by heating, and the necessity of sealing the container to exclude air.

After the publication and translation of Appert’s methods, commercial canning spread from France to England, where, in 1810, Peter Durand had obtained a patent covering the use of iron and tin to make canisters for preserving foods. John Hall, founder of the Dartford Iron works, and his associate, Bryan Donkin, recognised that these canisters would be a good outlet for their iron. They added food preservation to their enterprises and, after many trials, began to receive a favourable response from the British army and navy commanders.

By 1818 the Donkin and Hall products were being delivered in large quantities to many organisations, and especially attracted the attention of many great explorers, including Sir John Rose and Otto von Kotzebue.

The new food preservation method reached the United States about 1820, and there began to grow into the most important industry in the world economy. This extensive growth of commercial food was greater in the United States than anywhere else. Important factors in the industry’s growth were that continual changes and adaptations were made to containers, and the machinery and the equipment used to fill them.

Over 150 years ago people could buy peas, sardines and tomatoes in cans. However the cans were so heavy that they had to be taken home in a wheelbarrow, and often had to opened with a hammer and chisel.

In Britain, fruit canning as a major industry started about 90 years ago, but it was not until about 1930 that food in cans became part of everyday life. In the Second World War, food shortages meant that canned food was essential, both for soldiers at the front and for the people at home. Bottles were used too, and today some foods that aren’t suitable for cans are still put in bottles.

Appert’s stout glass jars with their wired and waxed cork stoppers were difficult to handle and manufacture. They were expensive to produce, as each one was hand-blown. The American glass container industry was slow to develop so the canning industry gradually began to recognise metal containers as more practical. In 1839 Kensett and Underwood, large manufacturers of jams, began packing their preservatives into metal canisters. They used a handmade canister, and it is that word which eventually became the recognised name of canning for the process of sealing and sterilising foods. ‘Canister’ comes from the Greek word kanastron meaning ‘basket of reeds’. In the early nineteenth century, coffee, tea, spices and fruits were stored in reed baskets, so when Durand patented his metal container, he called it a tin canister. It was in America that the name was shortened to can, and the word came into recognised usage.

As the demand for glass bottles increased in the 19^th century, more rapid means of production were necessary. Entire bottles were blown into hinged moulds, which could be opened for bottle removal. The first practical machines for blowing bottles were developed at the beginning of the 20^th century. The invention of the individual section machine in the 1920s allowed the continuous blowing of bottles.

There has been a trend towards the use of lighter-weight glass and sealing liners for the closures, as well as wider mouthed bottles and jars. As well as the bottles all being made by machine, sealing closures are also. The filling of glass containers with food is done by automatic machinery. Modern glass jars are all very similar. And are extremely resistant to heat and mechanical shock. The use of glass containers was expanded during the Second World War as Japan seized many tin-producing areas of Asia, leading to the shut off of tin shipments.

Before the twentieth century, canisters were made by hand. Tin-plated sheet iron was imported and cut with shears to form the body of the can and the circular top and bottom. The body was rolled into a cylinder and soldered along the side seam. The bottom and the top, in which a hole had been cut, were then joined to the body manually and held in place with more solder.

Once the can had been joined, it was filled with food. When it was full, a tin disc would be placed on top and soldered into place. This can of food could then be processed.

This process was known as the "hole-in-top" can, and about 60 cans could be made in a ten-hour day. In a modern factory today, more than 1000 cans are produced by one assembly line in a, minute.

By the twentieth century, the production of cans had changed dramatically. Cans were being cut out by foot pressers and other semiautomatic tools rather than by hand-shears. Then ‘crimping’ was introduced, where parts are joined and locked by crimping them together. This new can was known as the "sanitary" can as solder was only used on outside seams and the whole operation could be completed by automatic machinery. Gradual improvements have also been made in better lining materials for the cans such as lacquers and enamels. Other developments include the use of cans made of aluminium (which has a longer shelf life), very thin steel, and coated and un-coated plastic. Can openers are unnecessary for cans that have a metal tab or ring attached at the top for pulling open.

A "tin can" is not actually a very accurate description. Tin cans are made from steel sheets that are coated with tin, through dipping or electroplating. The actual percentage of tin in a tin can is about 0.25% - 2%. Because of the demand for tin cans in the 19^th century, a special branch of the steel industry was established, which produced steel more suitable for tin plating. Improvements have been made in the tin plate mills, and the present tin can is made by one of two methods, either hot-dip tinning, or electrolytic tinning. The latter is a continuous process.

Mrs. Beeton’s Household Management.

Nearly 29 million metal and glass containers are packed every year by the American canning industry and many container sizes have been standardised to aid production and processing.

The high percentage of water in most fresh foods makes them highly perishable. They spoil or lose their quality for several reasons:

· Growth of undesirable micro-organisms

· Activity of food enzymes

· Reactions with oxygen

· Moisture loss

Micro-organisms live and multiply quickly on the surfaces of fresh food and on the inside of bruised, insect damaged and diseased food. Oxygen and enzymes are present throughout fresh food tissues.

Proper canning practises include:

· Carefully selecting and washing fresh food

· Peeling some fresh foods

· Hot packing many fresh foods

· Adding acids (lemon juice or vinegar) to some foods

· Using acceptable cans, jars and lids

· Processing container in either steam or water for the correct period of time.

Collectively these practises remove oxygen, destroy enzymes, prevent the growth of undesirable bacteria, yeast’s and moulds, and help form a high vacuum in containers. Good vacuums form tight seals that keep liquid in and air and micro-organisms out.

In food-preservation, canning works very well, but is expensive and not totally efficient. For a tin of meat enough heat has to be applied to ensure the meat at the centre of the can is cooked, but this could result in the meat on the outside being overcooked.

Retortable pouches came about due to the needs of the twentieth century American army. The catering corps was asked to find a replacement for the heavy and bulky tin cans.

The pouch has many qualities that make it highly suitable for its job. It has a reliable seal, long-term storage capabilities, and the ability to contain nutritious food that need not necessarily be cooked and that soldiers would rather eat than throw away. It is also light and flexible. The polyester is tough and accepts printing, the aluminium foil is a seal against light and air and polypropylene plastic seals the food in the pouch. Raw food is placed in these pouches, which are then sealed and put into a steam-pressured retort. The cooking, as always, kills the bacteria in the food and inactivates the enzymes, ensuring that the food remains edible almost indefinitely.

The food, in theory, should be tastier than that in tin cans, as less heat is used to cook the food. This is due to the flat shape and the thinness of the materials.

These pouches are used a lot in Japan, and the US army, but apart from that the idea has never really caught on. This is mainly due to economics. Millions have been invested into canning techniques, and at the moment only a 120 pouches can be filled every minute. If the pouches become more available in Britain, consumers will have lighter shopping baskets and cheaper electricity bills, because retortable pouches do not need to be kept cold.

It is used for liquids like milk, fruit juices and custard, which are sterilised at high temperatures. Cartons are sterilised with hydrogen peroxide; this method was banned in the US until 1981. A method patented in Britain is allowed in the United States. Only 1% of Hydrogen Peroxide is used in the solution, then ultra violet light decomposes the solution to water.

Aseptic packaging could also be used for other foods, such as soup, fruit, and vegetables that are traditionally frozen or canned.

The carcass is put in a bag and the air sucked out. Then it is plunged in hot water to shrink it. By excluding oxygen from the meat, one set of spoilage bacteria can be stopped, although they are still in the meat and will become active is the package is removed, damaged or punctured.

Glass is one of the oldest of the packaging materials. Glass making is a huge business and glass is a very popular choice for some foods. Its advantages are that it is resealable, transparent, reusable and does not affect the taste of the contents among many things.

After mixing the batch is fed into the mouth of a furnace and is melted at temperatures of around 1500ºC. This temperature is reached from burning oil in the regenerators. After melting in the furnace, the molten glass moves along a shallow channel called a ‘forehearth’, where it is conditioned to ensure that at this stage a constant temperature is achieved throughout the glass. Depending on the type of container being made, the temperature may be around 1100ºC.

After conditioning, the glass is pushed down through an orifice-ring, which is like a bowl with a hole in it. A pair of shears then cuts it into gobs. The gobs then drop into the forming machine.

The containers are then reheated to anneal them. They then go onto a conveyor belt where rejected containers are sent back to be crushed and remelted. The glass containers are sprayed with chemicals to make them strong, then checked for faults automatically and manually. The containers are then put on pallets and shrink wrapped. After this forklift trucks carry the packages to delivery lorries.

The most commonly used forming machine nowadays is the independent section machine. This may consist of up to ten sections, working side by side, and two gobs can be made into containers at any one time on each section. Some machines can produce around 140 containers a minute.

The picture on the following page shows the complete process of making glass containers. The numbers in the text relate to this picture.

The two main ways of making glass containers are known as the "blow and blow" and the "press and blow" methods:

Tin plate and aluminium are a used a great deal in packaging, to produce cans, aerosols, foil containers and metal closures. There are various ways to make cans. Some cans are made of three pieces of metal (tinplate) - most food cans are of this type. Other cans are made from two pieces of metal (either aluminium or tinplate) and are used mainly for pet foods and drinks. About half of these drinks cans are made from aluminium, the rest are made from tinplate.

Canned food keeps well. As long as the cans are kept in a cool, dry cupboard, the food can last for months or even years.

Steel plate is shipped to the can maker from the steel mill either in sheets or coils. When shipped in coils, the can manufacturer cuts them into sheets. This coil-cutting process is among the technological advances that have allowed the industry to produce quality containers, economically priced. In recent years steel mills have begun producing "double reduced plate." The steel gains extra hardness when it is rolled to half its original thickness. This plate has better qualities - especially greater structural strength, allowing the can to be made from a thinner, lighter piece of steel. The disadvantage is that it is more brittle than other steel.

For carbonated drinks and aerosols, the strength of the round can is very important. However with food which must have equal heat distribution, square cans work better.

The golden colour seen on the inside of some cans is an enamel lining.

Lots of products require special coatings inside the can to protect them from metal contamination or to preserve their colour and flavour. Coatings also prevent rust and corrosion, may reduce the cost of cans by using less tin coating. No one coating is suitable for all purposes, making coating technology an important link with can manufacturing.

The stages they go through in canning the tongues are:

1. Everyone who enters the factory must be clean and wearing the correct overalls.
2. The tongues are checked for quality and prepared for canning
3. The cans are cleaned by powerful blowers and rinsed in purified water.
4. As the open cans move along a conveyor belt, the tongues are put into them, (for other products here is where liquid - brine for vegetables, syrup or fruit juice for fruit – would be added).
5. They are then moved on to a can-closing machine, and sealed. Each can is checked to make sure it has the right content level: any short-filled cans are automatically rejected.
6. The cans are placed into a machine rather like a giant pressure, called a retort. The tongues are cooked and sterilised, and the cans are cooled.
7. The conveyor moves on again. At this stage the cans are put in 24s and the outer packaging is put on. They are placed by hand into cardboard boxes and the whole pack is then shrink wrapped in film and heat-sealed.
8. The final stage comes when the trays are loaded onto pallets and taken to a warehouse.

There has been a rapid growth in the number and range of convenience foods available but the most convenient of these is the tin can.

The main advantages of canned food are:

· Availability – canned fruit and vegetables are available all year round, not just when they are in season.

· Variety – there is a huge variety of canned products available.

· Storage – canned food is easy to store. Qualities are maintained longer than other processed food and there is no need for refrigeration or additional energy consumption.

· Exclusiveness – some foods, such as baked beans, are only available in cans.

· Nutrition – the nutritional value of canned foods is often equal to the fresh or frozen equivalent.

Despite all the advantages of canned food, the manufacturers are constantly researching and developing new technology, as mentioned in Chapter One. The four new developments mentioned are retortable packages, aseptic packaging, vacuum packing and permeable packing. Many goods can be obtained which use these methods of packaging. However, the tin can has been in use for 200 years, and is still by far the most popular way of food preservation. It will be hard for any new packaging to replace the tin can, without convincing consumers of its reliability first. However, the tin can has many faults; they are heavy, unattractive and many of the newer developments would be better for the environment.

Manufacturers are constantly looking for new methods of food preservation. This is because they are dedicated to maintaining and developing high safety standards, faster processes, higher product quality, saving time and energy and producing less waste.

Whilst conducting this study I have discovered many new things about food preservation. At first I though it would only cover a small area of packaging, but once I looked into the history of it, I realised that preserved food was not always just for the convenience of having a meal in the cupboard that just needed reheating. By the cavemen making sure they had kept enough food to get them through a period without a successful catch, they ensured the well being of their family. Canned food provided lifelines for soldiers and people at home during the Second World War. The most important thing about preserved food that I found out was that over the centuries preserving food has been way of securing the future of humans.

I found my tour of Ham Packers Limited very thought provoking. It was the first I had been in a factory and I found the amount of machinery and technology involved staggering Although they have staff who oversee the procedures, most of the work is done by machine, from the making of cans, to the sealing, and then the heating. At no point were the cans touched by hand, just moved by complicated conveyor belt arrangements from one station to another.

This case study involved a lot of research, from reference books, companies and computers. Although most of the information was not readily at hand, the quality of information I did find was mostly excellent. I feel I have benefited from using so many different resources, as it gave me the opportunity to look at the subject from many different angles, and then select the parts I felt relevant.

Overall I found this case study very interesting. I feel I have learned much about something I before knew very little about. Because of this and the fact that my title provided me with a lot of different areas to research, I feel I have produced a good, in-depth look at the methods used in food preservation.

History of Canning

Automatic Canning Machinery

Recycling

Pollution

History of Packaging

The Food Canning Process

Pollution

Making Glass Containers

Recycling of Glass

The First Tin Cans

Material by Material Guide to Recycling

Food Packaging

Canning (past, present, future)

Retortable Pouches

Aseptic Packaging

Vacuum Packaging

Permeable Packaging

Domestic waste

Recycling Glass and Metal

Leaflets/Pamphlets -

The History of Canned Food

Convenience Food

The Canning Process

The Tinplate Cycle

Packaging Saves Waste

Recycling: is it the Whole Answer

Technology in Packaging

History

How Food is Canned

History and Development

The Advantages of Canned Food

Canning

Glass

Bottles and Containers

Iron and Steel Manufacture

Mining

Nicolas Appert

Bottles

Canning

Glass Blowing

Why Can Foods