200 DOMESTIC ANIMALS, DAIRYING, ETC. 



It would be just as illogical to condemn the whole group of bacteria 

 because a few are disease germs. Not more than one per cent of all 

 bacteria are harmful to man. The ninety-nine per cent are bene- 

 ficial and are absolutely necessary to the existence of life on the 

 earth. Many bacteria are out of place when in our food, though 

 they may be perfectly harmless. Here they are performing their 

 natural functions in changing and breaking down materials, which 

 work is essential in the soil, but not in foods. They are striving to do 

 in milk what they were created to do in the products necessary to 

 be changed for the growth of plants. 



The number of organisms that get into milk is proportionate 

 to the carelessness and ignorance of the producer. The question of 

 the numbers of bacteria that get into milk is not so serious as the 

 power of growth or multiplication of those that do get in. For ex- 

 ample, a bacterium will divide into two bacteria in twenty or thirty 

 minutes, according to the temperature, and again these two into four 

 in another twenty or thirty minutes, and so on in geometrical 

 progression. So that a bacterium given sufficient food and proper 

 conditions would multiply into a mass the size of the earth in five 

 days and eight hours. But yet the question of multiplication is not 

 so serious as the KINDS of bacteria that get into milk. 



Ten typhoid bacilli in a quart of milk are a source of disease 

 and even death to the consumer, while the three hundred millions 

 to six hundred millions of lactic acid bacteria per cubic centimeter 

 in sour milk and butter-milk render these products not only harmless, 

 but excellent and strengthening articles of food. The settling of 

 a limit by boards of health for the numbers of bacteria that a cubic 

 centimeter of market milk shall contain falls far short of the real 

 requirement. The question should be, are those present harmless 

 or dangerous? The ideal market milk would be milk entirely free 

 from bacteria, but under present conditions this ideal is an impos- 

 sibility. On the other hand, milk to be used for the making of butter 

 and cheese must contain certain kinds of bacteria for the proper 

 ripening of cream and cheese. These kinds which are necessary 

 to the creameryman are the most difficult ones to keep out of milk. 

 (Conn. B. 51.) 



Why Cold Aids in Preserving Milk. Dairymen at the present 

 time understand that milk is sure to contain bacteria in greater or 

 less numbers, and that these bacteria are the cause of the various 

 changes characterizing the spoiling of milk. It is the type of bac- 

 teria known as lactic bacteria that is responsible for the souring of 

 milk and all of the other changes which are liable to prove trouble- 

 some to the dairyman, slimy milk, bitter milk, etc., etc., are to-day 

 well known to be due also to bacteria in the milk. It is not simply 

 the presence of bacteria in the milk that produces these changes, 

 but rather their growth and multiplication. If they did not multi- 

 ply at all, the milk would not sour; the more rapidly they multiply, 

 the quicker the changes of the milk take place; the longer the 

 growth may be delayed and the slower it is, the longer the milk 

 may be retained in its fresh condition. These facts arefunda- 



