78 THE MILK QUESTION 



cleanliness and apply sufficient cold, with almost no in- 

 crease in expense, to supply milk twenty-four to thirty-six 

 hours old which will not contain, on the average, over 

 50,000 bacteria per cubic centimetre in winter and 100,000 

 in summer; and that milk containing more bacteria than 

 this should not be used. 



The above figures apply to standards that have been 

 recommended for market milk. The high figures are not 

 high standards. A limit of 500,000 bacteria per cubic 

 centimetre is rather a low standard and an admission that 

 better milk can hardly be obtained under present condi- 

 tions. In time these figures will doubtless be reduced. So 

 far as milk for infant feeding and other clinical purposes is 

 concerned, the standard established by Coit of 10,000 

 bacteria per cubic centimetre as a maximum for certified 

 milk seems, by unanimous consent, to be the best. Some 

 communities have adopted a second grade of milk, known 

 as "inspected milk from tuberculin-tested cattle," obtained 

 under cleanly conditions and not containing over 100,000 

 bacteria per cubic centimetre. 



The number of bacteria, therefore, allowable in milk de- 

 pends upon its grade and the purposes for which it is used 

 and varies somewhat with the locality. It is evidently 

 much easier to obtain milk containing fewer bacteria in 

 small communities with a near-by supply and in cold cli- 

 mates than it is in large cities with inevitable delays in 

 transportation or in Southern latitudes. 



As a general rule, then, it may be said that certified milk 

 should never exceed 10,000 bacteria per cubic centimetre; 

 inspected milk, not over 100,000; and health officers should 

 aim to keep the general milk supply below the 100,000 

 mark. 



The kinds of bacteria in milk. We still lack satisfactory 

 routine methods to determine the kinds of bacteria which 

 populate milk. The real harmful varieties, such as the 

 typhoid bacillus, the diphtheria bacillus, the tubercle 



