112 BACTERIA AND FOOD 



Foods like crackers, cereals, flour, do not decay even in warm 

 weather, because they contain less moisture than is needed for 

 bacterial growth. Meats, fish, fowl, and milk contain abundant 

 moisture, and bacteria develop rapidly in them. Dried fruits 

 such as apples, apricots, figs, prunes, give the dealer little trouble ; 

 fresh fruits cause him much loss. He keeps dried beef easily 

 for weeks and months ; but fresh meat he must preserve with 

 low temperatures. The Indians knew the value of drying meat ; 

 they cut the buffalo, deer, and bear killed on their hunt into long 

 strips and dried them in the sun and wind. The dried meat 

 was their main food during the long idle months that often 

 passed before the next successful hunt. Flour, barley, oat- 

 meal, and crackers protected against moisture do not decay; 

 water-soaked flour, barley, oatmeal, and crackers decay rapidly. 

 The surest way to protect foods against mold and decay is to 

 keep them cool and dry. A cool dry cellar, pantry, or refriger- 

 ator is an essential part of a large household. 



But drying is not so popular a preservative as low tempera- 

 ture because dried meat is tough, less digestible, and of a poorer 

 flavor than fresh meat. Dried fruits, such as raisins, pranes, 

 apples, apricots, and dried vegetables, such as lima beans and 

 corn, are not so tasty and palatable as fresh fruits and vegetables, 

 but they are widely used in winter because they are cheap and 

 nourishing. 



Salted meats and pickled vegetables. Bacteria cannot 

 grow and multiply in sugar, salt, or vinegar. Preserves rich 

 in sugar are not apt to spoil ; preserves made with little sugar 

 spoil readily. The best way to preserve fruit is to use equal 

 parts of sugar and fruit. Jelly is seldom spoiled by bacteria 

 because it contains so much sugar that they cannot grow in 

 it. Milk may be preserved by sugar; condensed milk is 

 milk from which the- water has been removed, and to which 

 a large quantity of sugar has been added. Candied and pre- 



