572 



ANNUAL REPOKT OF THE 



Off. Doc. 



of milk, it is well, at the same time, to aerate it, in order to remove 

 the natural ''jniimar' odor or any other odor that mav have been 

 absorbed hy the milk after milking. There are several special forms 

 of aeratoi's in the market (see Figs. 1 and 2) that serve for both cool 



FiR. 1. 



Pig. 2. Cliampioa cooler aud aei-atoi'. 



ing and aerating the milk at the same time. The main points to 

 be considered in selecting an aerator or a combined aerator and 

 cooler, are simplicity of construction, ease of management, effective- 

 ness in cooling and aerating aud convenience in keeping clean. 

 Aeration must always take place in an atmosphere as free as possible 

 from bacteria; otherwise the process will only increase the number. 

 The use of low temperatures in keeping milk gives the best results 

 onlv with the milk that is most free from bacteria. 



15. Destroying Bacteria in Milk. 



In the case of milk that contains large numbers of germs, the 

 most effective way to keep the milk from souring and from the devel- 

 opment of other forms of fermentation is to destroy the bacteria. 

 This may be best accomplished by heating the milk. While it is 

 possible to add to milk chemicals that will destroy bacteria without 

 affecting the composition or taste of the milk, the use of preserva- 

 tives is very generally condemned for this purpose on the ground 

 that they may injuriously affect the health of people using milk 



