CATTLE PRODUCTS 351 



to 50 F. or below. This will check the multiplication of 

 bacteria that would spoil the milk (Figs. 217, 218). 



EXERCISE. Temperature and Souring. Get two bottles 

 of milk, both fresh. Set one in a cool place where it will not 

 quite freeze. Set the other in a warm room. Notice the 

 difference in time it will take to sour the two bottles of milk. 

 These samples may be tasted for sourness and also tested 

 with blue litmus paper. 



FIG. 217. Fia. 218. 



FIG. 217. Milk bottles with crushed ice in shipping box. 

 FIG. 218. Delivery of milk to city houses. 



Bottling Milk and Cream. Milk and cream to be deliv- 

 ered directly to the users should be put into sterilized bottles, 

 which are kept covered and cold until the milk is used in 

 the home. The old way of delivering milk from cans which 

 were opened in the streets to take out the milk for each cus- 

 tomer, allowed dust and all kinds of city bacteria to get into 

 the milk. Simple machines are used by which milk and 

 cream may be put into bottles very rapidly with little hand- 

 ling (Fig. 219). 



Special Forms of Market Milk. There are laws or certain 

 regulations in many places which require that milk shall be 

 of a certain quality or standard. 



