DESICCATION 171 



Inhibition of microorganisms. It is impossible to pro- 

 duce and prepare foods without contaminating them with 

 microorganisms. No appreciable decomposition can take 

 place without the actual growth of the organisms. Any 

 1 ivatment that will inhibit or prevent the growth of bac- 

 teria and allied organisms will favor the preservation of 

 food supplies. Many chemical and physical agents influ- 

 ence the proliferation of microorganisms. 



Desiccation. Nature's method of protecting organic 

 matter from spoilage is by the removal of water. It is by 

 tar the most important way of preserving foods and fodders. 

 The great staple foods, grains, flours, meals, hays, and 

 other roughages, are thus preserved. Fruits as raisins, cur- 

 rants, and prunes are protected by drying in the sun. The 

 artificial dehydration of vegetables has made great pro- 

 gress and is destined to become more important as time 

 passes. The process obviates the transportation of large 

 quantities of water and the use of expensive containers. 

 When appropriate means of drying are used, the natural 

 flavor and texture of the original materials are restored by 

 allowing them to take up water. 



The dry foods absorb water if kept in a damp atmo- 

 sphere. The molds, due to their ability to secure water 

 where other organisms can not, are the first to appear on 

 the moist food. The molding of hay and grain are impor- 

 tant examples of the ability of molds to grow in the pres- 

 ence of small quantities of water. Meats, fish, eggs, and 

 milk are preserved by the removal of water. Edible oils, 

 such as olive and cottonseed, owe their keeping qualities 

 to their freedom from water. 



Preservation by concentration. In an earlier part of 

 this book the relation of the cell to the density of the 

 liquid surrounding it was presented. It was shown that 

 the ease with which the cell is plazmolyzed varies widely with 



