Food Preservatives and Butter Increasers. 



The subject of the preservation of articles of food against de- 

 cay is one of no little importance. Decay or fermentation is 

 known to be due to the action of living germs or ferments. If 

 in any way these germs can be destroyed or their development 

 prevented, without any change in the food product itself, it 

 seems possible that food might be preserved almost indefinitely. 



Two conditions that are absolutely necessary for the growth 

 and multiplication of these germs are a moderate temperature 

 and moisture. The methods most generally used for the preser- 

 vation of food aim to destroy these germs by depriving them 

 either temporarily or permanently of one or the other of these 

 conditions. These methods may be grouped as follows: 



1st. Those depending upon the use of heat for the destruction 

 of the germs and subsequent sealing to exclude other germs. 

 This principle is illustrated in the process of canning fruits and 

 vegetables. 



2d. Those depending ui)on the use of cold to prevent the mul- 

 tiplication of the germs for lack of sufficient heat. An example 

 of this is found in our extensive systems of cold storage. 



3d. Those in which the food product is dried in order that 

 the germs present may not multiply for lack of sufficient mois- 

 ture. The production of evaporated fruits illustrates this prin- 

 ciple. 



Where it is impossible to employ any of the above methods, or 

 where their use might injure or destroy some desirable quality of 

 the food resource is often had to the direct addition to the food 

 of some substance that is detrimental to germ life. The familiar 

 process of preserving meats, especially pork, by salting illus- 

 trates this class. There seems to be little or no objection to the 



