Methods of Canning and Preserving Foods

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There are numerous methods for canning and preserving food. Before trying any of these methods, be sure to research it thoroughly because improperly preserved food can carry bacteria and cause illness. Each state has an extension service that can provide you with information on how to safely preserve food.


Canning foods is basically putting food in jars or other containers and then heating them to destroy any bacteria that would cause the food to spoil. As the containers are heated, air is removed from them and creates a vacuum seal as it cools. This seal is essential to prevent any contamination from occurring.

There are two methods to canning foods; a boiling water bath method and a pressure canner method. The water bath method is generally used for fruits, jams, jellies, tomatoes, pickles, and other preservatives. The canning jars are completely covered in water and cooked for a specific time and temperature according to the food. The pressure canning method is used for meats, poultry, seafood, and vegetables. The jars are immersed in 2-3 inches of water in a pressure cooker. The temperature must reach at least 240 degrees in order to kill any bacteria.


Freezing is good for fruits, vegetables, meats, and other foods. Vegetables should be blanched before they are frozen. Blanching preserves the nutrients and color and also helps to clean it.

Be sure to use freezer-safe containers that have a tight seal. Food expands as it freezes, so always leave head space in the container for expansion. Freezing food does not improve the quality of it. Freezing does not kill bacteria, but it will prevent it from growing and multiplying.


Drying is the oldest method of preserving food. Ancient civilizations dried meats and fruits. The basis of drying foods is to remove the moisture from it. The best foods to dry are fresh fruits, vegetables, herbs, meat, and fish. The lack of moisture keeps bacteria from growing in the food. Food can be dried in the sun in hot, dry climates. It can also be dried in an oven or a food dryer/dehydrator.

Drying food in the sun is the old fashioned way and takes lots of time and patience. You must have bright sun, low humidity and day temperatures of around 100 degrees. You have to cover the food at night and make sure insects and dirt cannot get in. Depending on the food, it can take 3-7 days to dry it outside.

When drying in an oven, the temperature should be kept between 140-160 degrees. The oven door needs to be kept slightly ajar to allow moisture to escape. You can generally dry 4-6 pounds of food at a time in an oven. A fan should be place in front of the oven door to help the air to circulate.

Dehydrators are specifically designed to dry food. They keep a constant temperature of 140 degrees and has a built in air circulator. Food dehydrators come in many different sizes and prices, so research what you want before buying.

Smoking and Curing

Smoking and curing is another ancient method of preservation. Smoking and curing foods refers to adding salt, sugar and nitrates to food to preserve, color and flavor it. Fish and meats are the most commonly smoked and cured foods. Salt and nitrates remove moisture from the food to stop growth of bacteria. The nitrates also add to the color of the food.


Pickling is generally reserved for vegetables, meats and eggs. Pickling is done with either vinegar or salt. Vinegar is acidic and kills the bacteria present in the food. The salt method encourages fermentation and growth of good bacteria. Pickling often changes the color, taste and texture of the food, so you end up with something new and exciting. People have been pickling foods for thousands of years.

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