PART II 



Chapter I 



Cleaning and the Procurement of Milk 



CLEANING 



Systematic Cleanliness is the golden rule in dairy practice : 

 more than this, it includes all that is of prime importance in 

 Hygiene ; and it brings every one into actual contact with the 

 science of Bacteriology. Unfortunately it is only too obvious 

 that few people realise the true significance of cleanliness. For 

 example, in dusting a room, many think that they are serving 

 the interests of cleanliness by simply whirling up the dust with a 

 dry cloth from places where it is most conspicuous only to let it 

 settle in a thin layer all over the room after some time ; again, 

 many will wash a number of floors with the same pail of water, 

 which may at last become as black as ink, or wipe the inside of 

 cooking utensils with swabs which may be in a most disgusting 

 condition. It must also be said that most people consider the 

 daily brushing of their teeth with a tooth brush which is never 

 cleaned as the acme of cleanliness. 



As the great majority of the defects of milk and dairy products 

 arise through lack of cleanliness, a few remarks concerning the 

 cleaning of the surfaces with which the milk comes into contact will 

 not be out of place. If the cleaning is to be effective, the dirt must 

 not merely be spread over a larger area, but it must be completely 

 removed, and not only must the microorganisms present be killed, 

 but care must be taken that no fresh organisms are introduced. 

 The main object in cleaning is to get rid of the microorganisms, 

 and as these are usually embedded in the dirt, the first step is to 

 secure the removal of the dirt ; in doing this,, the great majority 

 of the microorganisms will be removed as well, while the few 

 which remain will be prevented from multiplying owing to lack of 

 nutrition. Moreover, even sterile dirt will always be undesirable 

 as it renders the surface of the vessel rough, and even if odourless 

 at the start, it will acquire an unpleasant taste and smell on being 

 submitted to the processes necessary for the killing of the micro- 

 organisms. In order to remove the dirt, which in our case con- 

 sists of the constituents of milk, it must be dissolved or at least 

 loosened ; thus fat will be loosened by the use of hot water. The 



