ANIMAL PRODUCTS 



chilled and dried ready for shipment 

 within 24 hours. 



Eggs in cold storage — Eefrigeration 

 of eggs has grown to be a business of 

 such proportions that more than $20,- 

 000,000 worth of eggs are annually held 

 in cold storage in this country. Re- 

 garding the practical details of cold 

 storage for eggs, Cooper has collected 

 some interesting information from men 

 who are engaged in the business. 



Temperature — For long storage 32° 

 F. seems to be the preferred temperature. 

 The actual temperature in different cold 

 storage plants ranges from 28 to 40° F., 

 but 28° F. is near the freezing point of 

 egg albumen and 40°F. is too high for 

 the effective preservation of eggs. Re- 

 cently there is a tendency to prefer 30 

 or 31° F. Most operators claim that the 

 lowest safe temperature is about two de- 

 grees below the optimum temperature. 

 Too low temperatures are said to pro- 

 duce dark spots, make the white more 

 liquid and injure the keeping quality of 

 the eggs. Eggs may be kept at a tem- 

 perature of 40° F. for three months, 

 after which they begin to get musty. 

 Cooper has shown that fresh eggs freeze 

 at 26 or 27° F., while sour or half rotten 

 eggs freeze just below 32° F. Eggs kept 

 between 28 and 30° F. for five months 

 will keep for three weeks longer after 

 removal from cold storage. Eggs must 

 be cooled down slowly when put in cold 

 storage, and warmed up slowly when re- 

 moved; otherwise the white becomes 

 thin and other bad effects are produced. 

 Humidity — The humidity of the air in 

 cold storage is an important point and 

 should be tested by means of a wet bulb 

 thermometer or hygrometer. The hu- 

 midity in plants actually in use for re- 

 frigerating eggs varies from 65 to 85 

 per cent, averaging about 75 per cent. 

 The percentage of humidity varies with 

 the season, ventilation and absorbents 

 ■used. It should be remembered that 

 the higher the temperature of the air, 

 the greater its capacity to hold water. If 

 the humidity is too low, the eggs lose too 

 much by evaporation, while if it is too 

 high, they become musty by the growth 

 of molds. On account of the danger 

 from the development of molds in high 

 temperatures it is evident that the higher 

 the temperature the lower must be the 

 relative humidity of the air for the sake 

 of safety. 



According to Cooper's tests the proper 

 relative humidity of the air at different 



temperatures is as follows: 28° F. 80 

 per cent, 29° F. 78 per cent, 30° F. 76 

 per cent, 31° F. 74 per cent, 32° F. 71 

 per cent, and 40° F. 53 per cent. It is 

 apparent from these figures that at a 

 temperature of 28° F. the high relative 

 humidity will largely prevent evapora- 

 tion from the egg into the air, while the 

 low temperature will effectively prevent 

 the growth of molds and bacteria. At a 

 temperature of 40° F., on the other hand, 

 the low relative humidity permits rapid 

 evaporation from the egg. Perhaps the 

 best_ instrument for determining the hu- 

 midity of the air in cold storage rooms is 

 the sling psychrometer devised by Prof- 

 essor Marvin of the United States 

 weather bureau. Tables are furnished 

 with the instrument by which the mois- 

 ture can readily be determined. 



_ Circulation— A good circulation of 

 air is necessary to the preservation of 

 eggs in cold storage. Circulation is re- 

 quired to equalize the temperature of all 

 parts of the cooling room, and to carry 

 away the moisture from the eggs to the 

 refrigerating pipes where it is condensed. 

 Gravity circulation is fairly well accom- 

 plished by placing the refrigerating 

 pipes near the ceiling and using false 

 partitions or false ceilings to direct the 

 cold air down by one course and the 

 warm air back to the pipes by another 

 course. If the arrangements for circu- 

 lation are poor, the temperature may 

 vary as much as five degrees in different 

 parts_ of the room. The greatest uni- 

 formity of temperature is secured by 

 keeping the pipes outside the room and 

 forcing the air by means of fans so that 

 it enters at one side and leaves at the 

 other side of the room. With proper 

 circulation it is safe to maintain a 

 higher humidity of the air and thus pre- 

 vent too great evaporation from the eggs. 

 Ventilation— The odors, gases and 

 moisture from eggs in cold storage are 

 partly collected by absorbents used in the 

 cooling room and condensed on the pipe3. 

 These means, however, are not sufficient 

 for removing all impurities, consequently 

 some ventilation is required. A little 

 air leaks in around windows and doors 

 but it is not enough and cannot be regu- 

 lated. Many cold storage operators do 

 not_ ventilate at all and, as a result, 

 their products possess a disagreeable 

 flavor and odor. In ventilating cooling 

 rooms for eggs, Cooper recommends that 

 the air be first cooled, dried and purified 

 before being forced into the cooling 



