The object of food preservation is to make fruits and vegetables of value for a longer time than through their ripening season. After ripening, fermentation and bacteriological changes take place so rapidly that the season for the usefulness of most fruits and of many vegetables is very limited unless some means is employed for their preservation.

Chilling, canning, drying, and pickling are the methods of preservation most commonly employed.

Chilling involves the keeping of foods at a very low temperature, a method which is only temporary but valuable and necessary both in the home and in the market. In cold, dry climates, chilling makes possible the keeping of many vegetables and some fruits throughout the winter without applying further means of preservation.

Drying is accomplished by exposure to the sun or to artificial heat. Drying is one of the oldest methods of food preservation and is valuable for many reasons. The dried food is light, compact, and easily handled; however, foods lose much in freshness and flavor when dried and become dark in appearance and small in size. Drying is unpopular because of the long soaking required before foods can be used, and because the commercially dried foods have often been treated with sulphur in order to preserve their color. Improved methods of commercial drying and dehydrating are today increasing the popularity of dried foods and offer a helpful solution to the ever-increasing problem of the high cost of living.

Canning is the method of preservation most generally employed for both fruits and vegetables. Canning of meat is also sometimes desirable on the farm when there are not means of keeping meat in hot weather, or when the feeding of poultry through the long winter season is not feasible. The thrifty housekeeper should be familiar with the most effective methods of canning in order to provide a varied diet for her family during the long season when fresh foods are not available.

Principles of Canning

Canning involves the destruction of all germs and spores by boiling or steaming the product, and the exclusion of all germs from the jar by completely sealing it. The destruction of germs in the food, on the jar and on everything that comes in contact with the food must be complete in order to secure success. Air-tight sealing of jars can be effected by using good tops and good, new, pliable rubbers, fitting them tightly. The best success in canning is usually obtained if small quantities of food are handled at a time. Small jars are preferable if the family is not large.

Methods of Canning

There are two methods of canning, known as the open-kettle method and the can-cooked, or cold-pack, method. The open-kettle method is more simple, but the can-cooked or cold-pack method can be used effectively with a larger number of foods.

Open-Kettle Method of Canning

In the open-kettle method the foods are brought to the boiling point in a kettle, boiled until thoroughly sterilized and tender, sweetened or seasoned as necessary, and then poured into sterilized jars, which must be sealed at once. This method requires but little time and a simple equipment will serve. It can be used to advantage with most fruits because it gives opportunity for evaporation of the water from watery fruits, for long boiling of such hard fruits as pears and quinces, and for the preparaton of jams, marmalades, and preserves. Because of the acids contained in fruits, they keep well when canned by this method. For this reason tomatoes can also be canned by the open-

kettle method, but other vegetables which do not contain so much acid will not keep.