CHAPTER VII 



PURE FOOD IN THE HOME 



Problems. i. To learn what causes food to spoil. 



2. To find out how yeast assists in bread making. 



3. To discover methods of keeping foods for long periods 

 of time. 



4. Why is there a difference in the efficiency of different 

 refrigerators ? 



5. To discover the most favorable conditions for the growth 

 of bacteria. 



Experiments. i. How and why yeast is used in bread making. 



2. What conditions are favorable and what unfavorable for the growth 

 of bacteria? 



3. What effects have different preservatives upon bacteria? 



Project I. TESTING AND PRESERVING EGGS FOR HOME USE. 



1. TESTING. Devise means for testing quality of eggs. (Candling; 

 10% brine solution.) Make test of fresh, stale, and good storage 

 eggs. (See United States Department Agriculture, Farmers' Bulle- 

 tin No. 471, and Sherman's Food Products, page 144.) 



2. PRESERVING. Methods in use? Principle of preservation? 

 Why must fresh, clean, and unwashed eggs be used when preserving 

 in water glass? 



3. COST OF EGG SUPPLY. Prices paid for eggs at different sea- 

 sons? 'How many eggs in a year? What saving would be made by 

 preserving three fourths of this supply? 



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