CHAPTER XXXVII 



THE KEEPING QUALITY OF MILK 



A COUNT of the bacteria in fresh milk, compared with 

 one made a few hours later, will frequently show that 

 the organisms have decreased in number. The decrease 

 is most pronounced at 70° Fahr., although the subse- 

 quent multiplication of the bacteria at this temperature 

 is more rapid than that at lower temperatures. The 

 examination of fifteen samples of milk from different 

 cows gave the following results: 



Number op Bacteria in 1 cc. op Milk 



40° Fahr. 55° Fahr. 70° Fahr. 



Freshly drawn 6,759 6,759 6,759 



After three hours 5,988 5,241 4,200 



After six hours 5,417 5,143 3,411 



After nine hours 5,929 5,311 3,947 



After twelve hours 5,188 5,370 6,341 



After fifteen hours 5,531 5,052 23,495 



After twenty-four hours.. 5,174 4,872 589,980 



After thirty-two hours . . . 5,067 5,399 



After forty-eight hours . . . 4,917 18,663 



The so-called germicidal power. — A decrease in num- 

 bers evidently occurred in every case. The diminished 

 number of bacteria in the fresh milk may be accounted 

 for by assuming that milk, as it is drawn from the 

 cow's udder, possesses a germicidal property that is 



(382) 



