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Canning is defined as a method of preservation of food, wherein the food to be stored is placed inside a can and sealed, so as to make it airtight and prevent any bacteria or harmful microorganisms from spoiling the food. Though canning only refers to the process of concealing the food in a container, there are several other types of processes that are used along with canning, in order to keep the food in an edible state for a longer duration of time. Popular canned dishes include preparations such as processed pre-cooked meats, canned fish, canned fruits and vegetables.

Canning is done when food is to be preserved for a longer duration of time.  The boiling water method for storing canned foods is generally works for tomatoes, fruits, jams, jellies, pickles and other kind of preservatives. The other option is pressure canning which is an appropriate and a safe method for preserving vegetables, meats, poultry and seafood. Under this method of canning, food jars are placed in water in a pressure cooker, which is then heated to a certain temperature to kill the micro-organisms.


Origin of Canning

The origin of the process of canning dates back to the times of the Napoleonic wars, when the government of France was ready to reward any person who could develop an inexpensive but effective way of preserving food. The reward amount is said to have been 12000 francs, which was a lot of money, but the army required food that they could keep with them for the long duration of the war, so it became a necessity to devise such a method. In the year 1809, a French person named Nicholas Appert, who was a brewer and confectioner by profession, initiated the canning process by cooking food in jars and keeping it airtight until the time of consumption. This is how the canning process was invented as a method of preserving food, and with the passage of time various canned recipes came into existence. Although canning originated in Europe, it soon spread to all countries of the world, and today canned dishes are a part of every cuisine, with canned products being use in almost every household and commercial eatery.


The Process of Canning

The process of canning can be carried out in two different ways; pressure canning method or a hot water bath method. The method of canning required by a foodstuff generally depends on its acidity, or ph level. Foodstuffs with very high acidity can be easily canned without much processing. Low acidity foods can sustain by either increasing their acidity or canning them using the hot water bath method, whereas foods with very low acidic level require pressure canning method to preserve them for a long duration of time. The difference between hot water bath and pressure canning is that while hot water bath only requires the canned food to be immersed in a container of hot water, pressure canning is carried out by placing the food in an enclosed container, which does not allow the steam to escape, thus applying pressure. The time taken in preparing canned dishes depends on the process of canning used, ranging anywhere between 10 minutes and 120 minutes. Canning requires the use of an open or closed container for heating water and canning equipment such as jars or tins in order to seal the food into cans. Canned dishes are commercially available and most people prefer to buy canned products, although it can be done at home as well.


Popular Canned Dishes

Some of the most popular canned dishes include canned tuna, sardines, bacon, baked beans, pineapples and a huge variety of pickles, chutneys, condiments and sauces. Although canning does not provide 100% safety from harmful microorganisms, almost every type of food ingredient can be canned in one way or the other, in order to increase its shelf life. Canning is practiced in almost every cuisine of the world, as canned recipes like pickles, jams and relishes are to be found in the cookbooks of every cuisine.


Advantages and Disadvantages of Canning

The major advantage of canning is that it prevents the growth of harmful bacteria and helps to keep the food fresher for longer. This is especially useful when preparing recipes which require seasonal ingredients; as such ingredients are not available at all times of the year. However, the disadvantage is that canning process does not fully eradicate the chances of microbial growth. Some spores and other types of thermally resistant bacteria can still grow on the food. Canning also needs to be coupled with other methods such as freezing, drying, boiling or pasteurization, in order to prevent the growth of bacteria while the food is kept inside the can.



• Some canned foods will never spoil till the time they are opened, in case the processing is done in the correct manner.

• A cloudy brine or liquid inside a can is generally an indication that the food is not suitable for eating.

• The number of canned foods manufactured across the globe in one year exceeds 2 billion.