Methods of Preserving Food

This is from my son's school assignment. It might be helpful for those researching for the same topic. I hope it helps.

Ways Of Preserving Food:

1. Freezing. Foods which spoil readily are frozen for transportation, and must be kept packed in ice until used. Examples: Fish and poultry.

2. Refrigeration. Foods so preserved are kept in cold storage. The cooling is accomplished by means of ice, or by a machine where compressed gas is cooled and then permitted to expand. Examples: meat, milk, butter, eggs, etc.

3. Canning. Which is preserving in air-tight glass jars, or tin cans hermetically sealed. When fruit is canned, sugar is usually added.

4. Sugar. Preserving in sugar or syrup. Examples: fruit-juices and condensed milk.

5. Exclusion of Air/Vacuum sealing is a fast and efficient way to prolong the life and freshness of food. Preservation relies on taking away one or more of the elements that cause food to deteriorate. Vacuum sealing takes away the oxygen that microbes need in order to break down food. Appropriate types of food are stored in an airless environment, usually in an air-tight pack or bottle to prevent the growth of microorganisms. Example: long-term storage of cereals, nuts, cured meats, cheese, smoked fish, coffee, and potato chips (crisps), vegetables, meats.

6. By Drying. Drying consists in evaporation of nearly all moisture, and is generally combined with salting, except in vegetables and fruits.

7. By Evaporation. There are examples where considerable moisture remains, though much is driven off. Example: beef extract.

8. By Salting. There are two kinds of salting, - dry, and corning or salting in brine. Salt is a preservative. When salt is applied in fish, the salt penetrates the tissues, drives out the water in the fish and settles in the tissue, which is why the fish tastes salty. Bacteria do not thrive in food with salt. That is why the food does not spoil and can keep longer. Examples: salt codfish, beef, pork, tripe, etc.

9. By Smoking. Some foods, after being salted, are hung in a closed room for several hours, where hickory wood is allowed to smother. Examples: ham, beef, and fish.

10. By Pickling. Vinegar, to which salt is added, and sometimes sugar and spices, is scalded; and cucumbers, onions, and various kinds of fruit are allowed to remain in it.

11. By Oil. Immersing in different oils (ex. Olive oil)

Examples: sardines, anchovies, etc.

12. By Antiseptics. The least wholesome way is by the use of antiseptics. Borax and salicylic acid, when employed, should be used sparingly.

13. Curing refers to various food preservation and flavoring processes, especially of meat or fish, by the addition of a combination of salt, sugar, nitrates or nitrite. Many curing processes also involve smoking.

14.  Dehydrating.  Drying by means of using a dehydrator machine. Example:  dried fruits. Dehydration is used to make packaged soups, coffee, tea and most spices. Dried foods can be reconstituted by adding water or often simply consumed dry. Common dried foods we eat every day include raisins, plums and beef jerky.

15. Vinegar preservation. Vinegar is acetic acid. The use of acid like vinegar is one preservative used in many homes. A cucumber pickle is an example of this. Bacteria do not thrive in acid so that foods mixed or cooked with vinegar do not spoil easily.

- lifted from google