CHAPTER XIV 



PRESERVATION BY CANNING 



The addition of mild preservatives like sugar, salt, 

 spices, vinegar, etc., while it makes possible the preser- 

 vation of many kinds of food, very decidedly changes 

 their nature. The flavor is totally changed, and in some 

 cases the food is rendered less digestible ; hence its food 

 value is lowered. These methods of preserving food are 

 very useful for some purposes, but they cannot be used 

 for all kinds of food. In many cases the change of flavor 

 would be so decided and the change in the nature of the 

 food so great as largely to destroy the material for subse- 

 quent purposes. None of the methods preserve the food 

 iii anything like its natural condition. 



What is Canning .' 



A method of preservation based upon the simple plan 

 of keeping bacteria away from food products has been 

 devised in the last century. This has come more and more 

 into common use, until to-day it is employed to an almost 

 incredible extent. The method is spoken of as canning. 

 The food is not treated by any antiseptic for the pre- 

 vention of bacterial growth, but reliance is placed simply 

 upon devices for keeping all bacteria from it. If this can 

 be done, the food will not be subject to their action, and 



will never spoil. 



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