POPULAR SCIENCE 



SOME SCIENTIFIC ASPECTS OF 

 COLD STORAGE 



By INGVAR JORGENSEN, Cand. Phil. (Copenhagen), D.I.C., 

 Research Worker for Food Investigation Board, Department of Scientific and Industrial Research, 



AND 



WALTER STILES, M.A. (Cambridge), 



Professor of Botany, University College, Reading 



PART III V 



In our earlier articles we have pointed out that as regards 

 preservation in cold storage, foods fall into two groups, those 

 in which the material is held above the freezing-point, and 

 those in which the food is kept in the frozen condition. As 

 examples of the former we have selected fruit and chilled 

 beef, both of which present their special problems. In this 

 article we shall confine our attention to the special problems 

 presented when food is preserved in the frozen condition. 



There are several advantages in keeping produce in the 

 frozen as contrasted with the chilled state. Not only does the 

 lower temperature reduce considerably the rate of chemical 

 reactions which produce deterioration of the material, but the 

 growth of micro-organisms in the solid condition is inhibited 

 or takes place with extreme slowness. In consequence frozen 

 material can be kept in cold storage for a much longer period 

 than produce kept in the unfrozen condition. This may be of 

 the utmost economic importance, for when it becomes possible 

 to substitute freezing for chilling in the cold storage of any 

 food substance it may increase indefinitely the distance over 

 which such food materials may be conveyed. This can be made 

 clear at once by reference to the case of beef. In the chilled 



1 The scope of this article was planned by both authors at the same time as 

 that of the earlier articles in this series. Owing to illness abroad Mr. Jorgensen 

 has, unfortunately, not been able to take part in the actual preparation of this con- 

 cluding article. For faults of presentation I am, therefore, alone responsible. — 

 W.S. 



427 



