COMMUNITY SANITATION 



415 



Milk may be pasteurized and rendered free from disease 

 germs by heating it to a temperature of 68.3. C. (155 F.) 

 for half an hour, or 77 C. (170 F.) for five minutes 

 (Figure 366). If the milk is cooled quickly after this 



8. Dept. of Agriculture. 



FIG. 366. A Bottle Pasteurizer. 



process and placed in a cool place it will keep longer and 

 be a safe food for the baby. 



Preservatives. Milk and other foods are often pre- 

 served by means of chemicals which destroy the germs 

 and prevent decay. So general has this use of chemicals 

 as preservatives become, that stringent laws have been 

 enacted prohibiting the practice, or forcing manufacturers 

 to state on the labels the kind and amount of chemical 

 used. Many dealers in foods, and even housewives, argue 

 that such use of chemicals is proper, as the process is 

 cheaper than canning and it destroys germs in food. The 



