THE PRESERVATION OF FOOD BY COLD. 399 



thawing the same physical and biological changes occur as in frozen meat. 

 When fish and poultry are stored in the undrawn condition there is an 

 abundant supply of bacteria at hand in the intestinal contents ready to 

 multiply energetically during the chilling and thawing stages. Practically, 

 the presence of the entrails has been found objectionable in the case of 

 frozen poultry because of the ease and rapidity with which poisonous 

 decomposition changes take place in this kind of food. It is desirable 

 that skill and care in killing and dressing should be employed in the 

 preparation of frozen poultry, and that the chilling period should be 

 shortened as much as possible. The tendency of such food rapidly to 

 undergo decomposition changes after thawing should be clearly recognized. 

 Its sale as fresh or as chilled food is a fraud upon the purchaser. 



The nature and source of the bacteria which produce poisonous 

 changes in poultry are not definitely known, but there is some evidence 

 indicating that they belong to the para-colon group and that they are 

 derived from the intestinal contents of the fowls. 



EGGS. The cold storage of eggs is an industry which has attained 

 large proportions in recent years. A very constant storage temperature 

 between +0.5 and + 1 is essential for the best results. The humidity of 

 the atmosphere is also of very great importance, as a dry air causes 

 extensive evaporation from the egg and a too moist air favors the develop- 

 ment of microorganisms on the exterior of the shell and the absorption of 

 their products and even their penetration into the egg. A constant 

 humidity of 70 per cent saturation has been found to be the best. Storage 

 at this temperature and humidity greatly retards the growth of micro- 

 organisms and definitely inhibits the ordinary putrefaction of eggs. The 

 activity of the intrinsic enzymes of the egg are not necessarily inhibited 

 by this temperature, nor is the growth of all microorganisms prevented. 

 Unquestionably there is a marked difference between the ordinary cold- 

 storage egg and the strictly fresh egg, but to what extent this deterioration 

 may be due to errors in storage such as inaccurate control of temperature 

 and humidity, use of odoriferous crates for packing, decomposition 

 changes previous to storage, too rapid chilling of the eggs, or too rapid 

 warming of them after removal from storage, and to what extent it is 

 inherent in the most perfect cold-storage procedure, is still somewhat 

 uncertain. Doubtless a certain amount of deterioration, especially the 

 loss of the peculiar flavor of the fresh egg, is unavoidable in any method 

 of prolonged storage. The discrimination in price in favor of new-laid 



