HOW MAY WE KEEP FOODS FROM SPOILING? 341 



be taken in handling it so that dirt and disease germs 

 do not get into it. 



Milk should be kept cold and covered, from the time 

 it leaves the cow until the time it is used. Since milk 

 is the best food for young children and since a baby's 

 digestion is easily upset, we must keep milk free from harm- 

 ful bacteria. To kill bacteria without injuring the milk, 

 a process known as pasteurization is used. This is named 

 after the great French scientist, Louis Pasteur, who first 

 used the process to kill harmful organisms in wine. 



Demonstration 3. How to Pasteurize Milk. 



Fill each of two test tubes half-full of raw milk and plug both 

 tubes with clean absorbent cotton. Place one tube in a beaker 

 of water and heat it to 145 F. for 25 or 30 minutes, and cool it in 

 cold water. Set the two tubes aside so that they will both be 



Galloway 



Milk from this dairy is a safe food for babies. Why ? Name all the devices 

 which make clean milk possible. 



