CHAPTER III* 

 THE PRESERVATION OF FOOD BY COLD 



Introduction 



In recent times cold storage has become of very great importance 

 in the preservation of perishable food stuffs, and foods preserved by 

 cold usually command a higher market price than those preserved. by 

 other methods. This is probably due primarily to the fact that the 

 general appearance of refrigerated food resembles that of the perfectly 

 fresh article, in many instances very closely. Moreover, in many 

 instances cold storage, for a reasonable length of time, preserves not 

 only the appearance and the nutritive value, but also the chemical 

 composition, and even the delicate flavors of the original articles, so 

 important in determining market value. The great economic impor-:- 

 tance of this industry is at once apparent, for it aims to preserve un-r 

 changed the over-abundance of one locality for transportation to 

 another, and the over-production of one season of the year for subse-s 

 quent use. , 



The Effects of Refrigeration upon Foods in General 



The decomposition of foods depends upon the activity of their, own 

 intrinsic enzymes to some extent, but more especially upon the activity 

 of foreign microorganisms — bacteria, yeasts and molds. Cold acts as 

 a preservative, not by destroying these microbes, but by retarding of 

 inhibiting their activity. In general, cold not only retards the growth 

 of the microorganisms but delays their death also, tending to preserve 

 them as well as the food tmchanged. 



In discussing the refrigeration of foods we may consider three periods 

 of treatmejit, (i) the rejnoval of the heat or chiUing of' the food, (2) the 

 prolonged storage at low temperature, (3) the subseqiient warming of 

 the food before sale; or consumption. 



• Prepated by W. J. MacNeal. 



471 



