CHAPTER I 



INTRODUCTION 



It is only recently that the importance of tempera- 

 ture, pressure and humidity in relation to milk 

 handling has been fully realized. Authorities are 

 now agreed that the successful manufacture, han- 

 dling and storage of milk and milk products of prime 

 quality depend upon the knowledge and the careful 

 regulation of these factors. Cleanliness is not to be 

 minimized, but it is taken for granted in this dis- 

 cussion that every right-thinking dairyman has the 

 welfare of his community enough at heart to use the 

 utmost care in keeping his plant clean and sanitary. 

 Our aim is to give to the manufacturer, superin- 

 tendent and operator certain suggestions regarding 

 the relation of temperature, humidity and pressure 

 to dairy operations, which will not only enable him 

 to raise the standard of his product and eliminate 

 needless wastes, but in the end will be of assistance 

 to the whole industry. 



Temperature has two influences on dairy opera- 

 tions : it regulates the growth of micro-organisms, 

 and it has a physical effect on certain operations 

 and on the quality of the finished product. 



The Influence of Temperature on the Growth of 

 Micro-Organisms. 

 Every dairyman knows that in milk and milk 

 products there are many micro-organisms: bacteria, 

 yeasts and molds. Because these are really tiny 

 plants, their growth depends upon a readily avail- 

 able food supply and proper temperature. Milk and 



