CHAPTER XXIV 

 PRESERVING FOODS 



Germs which Help and Hinder. The farmer's 

 wife has her problems of canning fruits and pre- 

 serving foods. It is a help to her to know the ene- 

 mies she must fight and the harm they do. There 

 are three living organisms that will cause animal 

 or vegetable matter to decay. These are yeast, 

 molds, and germs, or bacteria. 



The Yeast Plant. In order to grow, the yeast 

 plant must have warmth, air, moisture, and sugar. 

 This plant grows and divides into two plants, and 

 these divide again and so on. Thus this tiny plant 

 multiplies amazingly in a short time. It will grow 

 in fruit juice and in fruit slightly sweetened, but it 

 will not grow in thick sirups or preserves. It is 

 easily killed by a high or low temperature. 



Making Bread. A small amount of yeast is put 

 in the dough to make it *^rise*' for bread. When 

 sugar is added, the plants increase in great numbers 

 in a few hours. They start the decay of the mix- 

 ture and create a gas which forms bubbles through- 

 out the mass, and these make the bread rise. When 

 the bread is baked the yeast plant is killed by the 

 heat, and the gas escapes. 



Mold. Mold is spread about by tiny spores or 

 seeds floating in the air. When they lodge on a 



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