The Production of Clean Milk and 

 Cream for Industrial Purposes 



CHAPTER I. 



Bacteria 



\Yhere Bacteria are the cause of nearly all the pro- 

 cesses of fermentation and deterioration in milk, and 

 therefore intimately connected with the question of clean 

 milk production, a short description of their nature seems 

 advisable for a good understanding of the contents of 

 this booklet. 



Bacteria are the smallest of living plants we know. 

 Each Bacteria is made of only one cell. The cell is com- 

 posed of a cell-wall with transparent contents, termed 

 protoplasm, of which the exact composition is not yet 

 known. 



Bacteria are very small. They can be observed and 

 studied only with the aid of a powerful microscope. 

 Some bacteria are so small that 25,000 could be placed 

 side by side and form a chain of less than one inch in 

 length. 



They are present everywhere ; in the soil, in the air 

 of rooms, stables and outside, in water, on all food stuffs, 

 on the milktools, adhering to the hairs of all animals, but 

 particularly in all decaying and rotting organic matter 

 like dung, sour milk, and fermenting foodrests. 



Under favorable conditions for their growth, billions 

 may be found in one cubic centimeter, (a cubic centimeter 

 is about 1-16 part of a cubic inch.) 



They grow extremely rapidly. One single bacterium 

 may grow to several millions in 24 hours. 



The reproduction takes place by division of cells, 

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