PRESERVATION OF EGGS
CAUSES AND PREVENTION OF DETERIORATION
24. As has been implied in the discussion given thus far, eggs will deteriorate or spoil in a comparatively short time unless something is done to preserve them. In view of the eggs she keeps on hand at home, as well as those she buys, the causes of spoiling and the ways in which to prevent spoiling are matters with which the housewife should be familiar, particularly if she would secure for her family eggs of the best quality at prices that are not beyond her means. The spoiling of eggs is due to decomposition, which is caused by molds or bacteria that result from accidental causes, and, in fertile eggs, to the germination and development of the chick, which is a natural process. The loss of quality resulting from molds and bacteria in the egg is brought about by their growth and by the formation of chemical compounds, which give spoiled eggs their peculiar appearance, taste, and odor. Some of these molds are not injurious to health, while others may give rise to more or less serious illness.
25. Various methods have been devised whereby their rapid deterioration may be prevented, and a knowledge of these is important to those who have occasion to purchase eggs or to keep them over from the season of plenty to the season of scarcity. The method followed to prevent losses due to the development of the embryo consists in the production of infertile eggs--that is, eggs that are non-productive. This is a point that is as well worth remembering in the home production of eggs as it is in professional poultry raising. The method employed to prevent the infection of eggs by molds and bacteria is to keep them clean and dry from the time they are laid until they are finally used.
26. While the preservation of eggs is carried on to a greater extent at present than formerly, the idea is neither new nor original; indeed, it has been practiced for many years by the people of some foreign countries. For instance, in some sections of China, duck eggs are preserved by covering them with a layer of mud, and such eggs are often kept for a year or more before they are eaten. However, eggs stored in this way decompose and their odor and flavor disappear before they are used, so that they must usually be hard boiled before they can be eaten. Egg preservation such as is practiced in the United States is the opposite of this and attempts to prevent not only ripening processes and putrefactive changes but any bacterial or other changes that lessen the original quality. It will be well to note, however, that eggs preserved for any length of time deteriorate to some extent and cannot be expected to be equally as good as fresh eggs.
COMMERCIAL PRESERVATION OF EGGS
27. The usual market method of preserving eggs is by cold storage, an industry that has developed to vast proportions in recent years. The success of this method depends on the fact that germs causing decomposition will not live in a low temperature. While the plan of storing eggs is responsible for their high price at certain times, it is also a means of supplying eggs to many persons who would otherwise not be able to obtain them. The greatest point in favor of this plan, however, is that it makes possible the marketing of quantities of eggs during the winter season of scarcity at a price that, although somewhat high at times, is much more moderate than it would be if it were not possible to store eggs in large quantities.
28. In order that advantage may be taken of favorable climatic conditions, eggs are commonly purchased for storage as early in the year as they are abundant. They are selected with great care, only those which are clean, sound, and fresh being used. These eggs are packed in clean cases, and then placed in warehouses where they are kept at a temperature just above freezing, or one that ranges from 32 to 40 degrees Fahrenheit. In such storage, precaution is usually taken to prevent the eggs from freezing, for while freezing does not necessarily injure them for immediate use it breaks the shell because of the contraction that occurs. While the eggs are in storage, they are also protected as far as possible from air circulation, as this increases evaporation and causes the contents of eggs to shrink. To prevent the yolks from settling to one side, and finally adhering to the shell, the eggs are turned frequently. The usual limits of storage are from 6 to 9 months, but eggs are not generally allowed to remain in storage more than 8 months. When taken out at the end of that time, it will be found that they have deteriorated very little, and while they cannot compete with the better grades of fresh eggs, they are as desirable as most of the eggs that can be purchased in the early fall when eggs are not plentiful.
29. Sometimes eggs are removed from the shells, stored for commercial use in containers of about 50 pounds each, and kept at the freezing point until they are to be used. Eggs in this form, which may be bought with the yolks and whites either mixed or separate, find a ready market in bakeries and restaurants, where large quantities of eggs are continually used. Such eggs remain good for any length of time while they are kept frozen, but they must be used immediately after they are removed from storage.
30. It is not always necessary to keep eggs at a cold temperature in order to preserve them, for a method that has proved very satisfactory is to reduce them to the form of powder by drying them. In this form, the bulk is greatly reduced, 1 pound of the dry material representing 30 to 40 eggs, and in order to prepare them for use in cooking they must be mixed with water. POWDERED EGGS, or desiccated eggs, as they are usually called, can be kept for an indefinite length of time without special care in storage, when they are wholesome and carefully handled. Tests that have been made show that eggs of this kind give fairly good results when used in cookery, but they are used principally by bakers, for they can be obtained more cheaply than fresh eggs, especially when it is difficult to secure eggs in other forms.
HOME PRESERVATION OF EGGS
31. The housewife who desires to run her household on an economical basis will not depend entirely on eggs that are commercially stored, but will take advantage of one of the many methods by which eggs may be successfully kept in the home. By being prudent in this matter, she will be prepared to supply her family with this commodity at times when the market price is high.
As many as twenty household methods have been tried out for the preserving of eggs, but each one is based on the theory that decay is hindered when the shell is covered with some substance that renders it air-tight and prevents evaporation or the entrance of bacteria and mold. Among the methods that have met with the most success are burying eggs in oats, bran, or salt; rubbing them with fat; dipping them in melted paraffin; covering them with varnish or shellac; and putting them down in lime water or in a solution of water glass.
No matter which of these methods is adopted, however, it will be well to note that only eggs laid in April, May, or June should be used for storage purposes, as these are the best ones laid during the year; also, that the eggs should always be packed with the small end down, because the yolk will not settle toward the small end so readily as toward the large end or the side.
32. Of these various ways of preserving eggs in the home, probably the oldest method is that of packing the eggs in oats, bran, or salt. This method is fairly effective, but the eggs preserved by it do not keep so long as eggs preserved by other methods, nor is their quality so good. Preserving eggs by completely covering the shells with fat, vaseline, paraffin, varnish, or other substance that will exclude the air but not impart flavor to the eggs, proves a more satisfactory method so far as the eggs are concerned, but it requires more time and handling. To assist in their preservation, eggs are sometimes immersed in boiling water for 12 to 15 seconds. This process, which causes the white to harden slightly just inside of the shell, keeps the eggs fairly well, but it is rather difficult to accomplish, as the least overcooking renders the egg unfit for use as a raw egg.
As a result of many trials, it has been found that putting eggs down in the various solutions that are used for this purpose is the most effective way of preserving them under home conditions, provided, of course, the solutions in which the eggs are immersed do not flavor the eggs. Therefore, to assist the housewife, detailed directions for using lime water and water glass for this purpose are here given.
33. PRESERVATION WITH LIMEWATER.--To prepare limewater for the preservation of eggs, dissolve 1 pound or 1 pint of salt and 1 quart of finely slaked lime in 3 gallons of water, stir the solution at frequent intervals for a day or two, and then allow the liquid to settle. Place the eggs in tall stone crocks or kegs with their pointed ends turned down, filling the receptacles to within a few inches of the top. Pour the clear limewater over the eggs so arranged, allowing it to rise an inch or two above the top layer. Then stand the vessel in a cool place where the temperature will not exceed 50 degrees Fahrenheit. Eggs so treated will keep for at least 6 or 8 months. The only objection to this plan is that the eggs preserved by it sometimes acquire a slight lime taste.
34. PRESERVATION WITH WATER GLASS.--Putting eggs down in a solution of water glass is without doubt the most satisfactory method of storing them in the home. So effective does this method prove that the housewife who has a convenient and proper storage room should not fail to take advantage of this way of laying up a supply of eggs.
The commercial form of water glass is usually a mixture of potassium and sodium silicate, which, besides being cheaper than that which is chemically pure, is the kind that is preferred for the purpose of preserving eggs. A good quality of it either in a sirup-like solution or in the form of a powder retails in drug or grocery stores for about 10 cents a pound. To make a solution of the desired strength to preserve eggs satisfactorily, dissolve 1 part of water glass in 7 parts of warm water that has first been boiled to drive off bacteria, mold, spores, etc. One quart of water glass will make sufficient solution to cover about 12 dozen eggs. With the solution thoroughly mixed, it is ready to pour over the eggs.
In selecting eggs for the purpose of storing, be careful to choose only those which are clean, fresh, and perfectly sound, and, if possible, infertile. It is advisable not to wash them before they are put into the preservative, for they will keep better if their bloom is not removed. Place the eggs in receptacles in the manner explained for preserving eggs in limewater, and over them pour the water-glass solution until they are all covered. If the eggs so prepared are stored in a cool place, they will keep as long as those preserved in limewater; besides, there will be no danger of their acquiring any foreign flavor.