Page:The New International Encyclopædia 1st ed. v. 06.djvu/786

* EGG. 682 EGG. parting an unpleasant flavor to the eggs. The liavor is also impaired when the air in whieh the eggs are stored is tainted by odors such as those of decaying vegetables, rancid fats, and gases of various kinds. Raw eggs or eggs only sliglitly cooked are com- monly said to be very digestible, the idea being obviously that they digest readily without giving rise to pain or other physical discomfort. This is in accord with the results of numerous experi- ments, which show that the length of time that eggs are cooked aiTects somewhat the time re- quired for digestion, and that some 9.5 per cent, of the total dry matter and 97 per cent, of the protein of eggs is digestible. It seems fair to conclude that the length of time of cooking has less etTect upon the percentage amount that may be digested than upon the time required for di- gestion. In a healthy man. the latter considera- tion is probably not a matter of much impor- tance: in the diet of sick persons and invalids. it may be more important. From the results of numerous dietary studies, it appears that eggs furnish 3 per cent, of the total food. 5.9 per cent, of the total protein, and 4.3 per cent, of the total fat used ]wr man per day in the aver- age American family. In this respect, eggs ■compare favorably with the more common ani- mal foods. M.VRKETIXG AND TESTING. In earlier times eggs, if sold at all, were marketed near the place where they were produced. JIany are still sold in local markets ; but with improved methods of transportation the market has been extended, and large quantities of eggs are shipped from tlie United States and Canada, not only to distant points in America, but to Eng- land and more distant countries. For shipping long distances, there are s]K'cial egg-cases. Eggs which are to be shipped, whether with or with- out a special attempt at preservation, should be perfectly fresh, and should never be packed in any material which has a disagreeable odor. -Micro-organisms enter the egg through the minute pores in the shell, and set up fermenta- tion, which ruins the egg. In other words, it leeomes rotten. The unpleasant odor of rotten eggs is due to the formation of sulphureted Tiydrogcn. The normal egg-shell has a natural surface coating of mucilaginous matter, whieh hinders the entrance of these harmful organisms for a considerable time. If this coating be re- moved or softened by washing or otherwise., the keeping quality of the egg is much diminished. If the process of hatching has begun, the flavor of the egg is also injured. There are many ways of testing the freshness of eggs which are more or less satisfactory. 'Candling" is one of the meth- ods most commonly followed. The eggs, when held against a light in a suitable device, appear luiclouded and almost translucent when fresh, and dark-colored if they are addled. A dark spot may be observed if incubation has begun, which in- creases in size accor<ling to the stage to which incubation has advanced. The age of eggs may be approximately judged by taking advantage of the fact that, as they giow old, their den- sity decreases through evaporation of moisture. According to Siebel. a new-laid egg placed in a vessel of brine made in the proportion of two ounces of salt to one pint of water will at once sink to the bottom. An egg one day old will sink below the surface, but not to the bottom, while one three days old will swim just im- mersed in the liquid. If more than three days old, the egg will float on the surface, the amount of shell exposed increasing with age; and if two weeks old, only a little of the shell will dip in the liquid. Methods of PBESEnv.^Tiox. Fresh eggs are preserved in a number of ways, which may. for convenience, be grouped under two general classes, which are often combined: (1) Use of low temperature, i.e. cold storage; and (2) ex- cluding the air by coating, covering, or immers- ing the eggs, some material or solution being used wliicl may or may not be a germicide. The first method owes its value to the fact that microorganisms, like larger forms of plant life, will not grow below a certain temperature, the necessary degree of cold varying with the species. It is stated bv Siebel that, in jjractice in the United States," 32° to 3:!" F. is regarded as the best temperature for storing eggs, although some American packers prefer 31° to 34°. English writers recommend a temperature of 40° to 45° as being equally satisfactory. Without doubt the amoimt of moisture in the air in the cold- storage chamber has an im])ortaut bearing on this point. Eggs are generally placed in cold storage in April and the early part of May: if later than this time they do not keep well. They are seldom kept in storage longer than a year. Eggs which have been stored at a temperature of 30° must be used soon after removal from storage, while those stored at 35° to 40° will keep for a considerable time after removal from storage, and are said to have the flavor of fresh eggs. Stored eggs should be turned at least twice a week, to prevent the yolk from adhering to the shell. Eggs are sometimes removed from the shells and stored in bulk, usually on a com- mercial scale in cans containing about fifty pounds each. The temperature recommended is about 30° F., a little below freezing, and it is said they will keep any desired length of time. They must be used soon after they have been removed from storage and have been thawed. The substances suggested and the methods tried for excluding air conveying micro-organisms into the egg, and for killing those already present, are very numerous. An old domestic method is to pack the eggs in oats or bran. Another, which has always had many advocates, consists in covering the eggs with lime-water, which may or may not contain salt. The results obtained by such methods are not by any means uniform. Sometimes the eggs remain fresh and of good flavor, and at other times they spoil. A method of preserving eggs, which has recently been often ised with much success, consists in pack- ing them in carefully cleaned vessels of suitable shape, and covering them with a 10 per cent, solution of water-glass (sodium silicate or potas- sium silicate). The shells of eggs preserved in water-glass are apt to crack in boiling, but, it is stated, this may be prevented by puncturing the blunt end of the egg with a pin before put- ting it into the water. In the East Indian .rchi- pelago salted ducks' eggs are an article of diet, the new-laid eggs having been packed for two or three weeks in a mixture of clay, brick-dust, and salt. They are eaten hard-boiled. In that region and in India, turtle-eggs are also pre- served in salt. These products, while unusual, do not necessarily suggest an unpleasant article