BACTERIOLOGICAL ASPECTS OF DEHYDRATION 111 



also affected almost every type of food substance. Because of 

 the necessity for sending these enormous quantities of bread- 

 stuffs abroad it has been especially desirable that the problems of 

 food conservation in this country should be studied with especial 

 care, to utilize as fully as possible all those methods of food 

 treatment which would make it possible to lessen waste and build 

 up a reserve against another period of shortage, bad crops, or 

 unusual exportation. These investigations had their first fruits 

 in the movement for war gardens and home canning and pre- 

 serving, and their later and more permanent results in the stimu- 

 lation of renewed interest in the great industrial methods of food 

 preservation, and particularly in the impetus given to drying as 

 a means of protecting foods against spoilage, and preserving 

 them for future use. Since the problem of spoilage is essentially 

 a microbiological problem, it follows that the investigation of 

 dehydration has manifold bacteriological aspects. 



Dehydration, desiccation, or drying as applied to foods, may 

 be defined as the process of removal of the surplus water from the 

 food substance in such a way as to prevent destruction of the 

 cellular tissues, maintain the energy values, and preserve poten- 

 tially the color, flavor and physical condition of the food. Since 

 practically all foods, with exception of the ripe seeds of cereals, 

 legumes, and a few other plants, contain a large percentage of 

 water and as a result have relatively short storage periods in the 

 fresh state, it is clear that the rapid, regulated drying of such 

 foods will, if it can be successfully accomplished, add greatly to 

 the world's stock in a form which is capable of easy storage, 

 favorable transportation and universal employment. More- 

 over, when we appreciate that approximately 50 per cent of the 

 total food produced in America in a single year never reaches 

 the consumer because of poor crop management, bad market 

 conditions, distance from means of transportation or losses en 

 route and in the city markets, the great possibilities of dehydration 

 begin to be apparent. Much could be said on the economic side 

 of this subject, but at this time I desire to emphasize especially 

 those phases which are of direct interest to us as bacteriologists, 

 physicians or sanitarians. 



