n6 PURE FOOD IN THE HOME 



Project II. To PASTEURIZE YOUR HOME MILK SUPPLY. 



If your milk is purchased is there any evidence to indicate whether 

 or not it has been pasteurized? What is the evidence? Reasons why 

 you prefer pasteurized milk? Devise apparatus for pasteurization. 

 What temperature will you use? Give in your report a full account 

 of new facts learned, diagram of apparatus, and results secured. 



Thought Question. 



In a test, 50 pounds of ice were put into the refrigerator on a warm, 

 muggy day. The refrigerator was opened when necessary to put 

 in and to take out food. All the drip water going from the re f rig- 

 erator was saved and weighed. It weighed more than 50 pounds. 

 Explain why. 



Why foods spoil. We are well aware that foods do not 

 keep indefinitely. Peaches, pears, and apples rot; eggs, 

 meat, and fish spoil; and milk and cooked cereals become 

 sour. Why does this happen? We know that if foods 

 are placed in the ice box they will not spoil so soon. We 

 know that if we boil certain kinds of foods they are less 

 likely to spoil, and we are all familiar with the use of canning 

 as a means of keeping foods ; but why do foods become 

 unfit for use eventually ? Take small quantities of several 

 different kinds of foods, for example, milk, a piece of 

 meat, potatoes, and cooked cereal, divide each food into 

 two equal portions, and place in separate dishes or jars; 

 seal tight. Place these jars in a large dish of water 

 and boil them for one hour. After this boiling we are sure 

 that everything that might have been living in the jars is 

 dead. If we now open one jar of each food, keeping the other 

 closed, and examine their contents after four or five days, 

 we shall find that in the open jars, the food has begun to 

 spoil, while in the closed jars, it is still good. Comparing 

 this with our previous experiments with the air, we may 

 conclude that whatever causes the food to spoil must come 



