MILK 79 



which comes from a clean healthy cow, is milked by 

 a clean person free from disease into carefully boiled 

 (sterilized) vessels, and is not afterward contaminated 

 by handling nor subjected to a temperature higher than 

 40 or 50 F., is so free from microbes as to be absolutely 

 safe. If the cow has some such disease as tuberculosis, 

 the milk, even when fresh, will often contain the germs 

 of the disease and thus be a most dangerous food. Dur- 

 ing the milking process, the microbe-laden dust and dirt 

 on the skins of the cows and on the hands of the milk- 

 men sometimes get into the milk in such quantities 

 that a cubic centimetre of fresh milk contains millions of 

 microbes. 1 Fortunately, many or most of these are not 

 ordinarily harmful, but one cannot be sure that this is 

 the case. After milking, the milk may be put into cans 

 which are full of microbes that will hasten its spoil- 

 ing ; the milk cans may even have been washed in water 

 contaminated with typhoid or other disease-producing 

 microbes, or handled by those who are themselves ill, 

 as has only too often been found to be the case in epi- 

 demics of typhoid and scarlet fever. The milk may 

 further be left uncovered so that the microbes carried 

 by insects or by the air find ready access to it. In 

 short, milk, because of its large use in the uncooked 

 or raw state, is subject to contamination on every 

 hand. 



Effect of temperature. In order to keep milk sweet, 

 it must not only be kept clean but in addition it must 

 be chilled as soon as it is milked and thereafter be kept 



1 The laws of Massachusetts permit 500,000 microbes to the 

 cu. cm. and consider such milk moderately clean. Of course, 

 these are not supposed to be disease-producing microbes. Their 

 number is considered to be a measure of the cleanliness of the 

 premises, the age of the milk, the care with which it has been 

 handled, and the temperature at which it has been kept. 



