234 AGRICULTURAL BACTERIOLOGY 



a special product, and its use is confined mainly to infant 

 feeding. 



The bacterial standard for certified milk is usually 10,000 

 bacteria per cubic centimeter. It is only by the exercise of 

 the greatest care at every point that the bacterial content 

 can be kept below this maximum. 



The term "certified milk" has been registered by Mr. 

 Francisco of New Jersey, who was the first to engage in 

 the production of such milk under the direction of the 

 Medical Milk Commission of Essex County, New Jersey. 

 The use of the term is allowed when the milk is produced 

 under the regulation of any medical milk commission. 



Most certified milk is now produced on fancy dairy farms 

 conducted by wealthy men. The barns and other equip- 

 ment are the best that can be obtained, and the methods 

 employed, as far as cleanliness is concerned, are extreme. 

 In some of the dairies the bacterial content is reduced to a 

 few hundred per cubic centimeter, or to that which is de- 

 rived from the interior of the udder. Such milk will, 

 when well refrigerated, keep for long periods of time. It 

 is a not uncommon thing for such milk to keep perfectly 

 sweet for from ten to fifteen days. 



Pasteurization of market milk. Milk may become con- 

 taminated with pathogenic bacteria from a multitude of 

 sources, none of which can be guarded against perfectly. 

 It is estimated that at least one person in each thousand is 

 a "typhoid carrier." It is impossible to detect which in- 

 dividuals are a menace to their fellow men in this respect. 

 Even when a typhoid carrier is detected, it is difficult to 

 control his movements so that he will not present a danger 

 to those with whom he may be, directly or indirectly, as- 

 sociated. 



The larger cities have realized the impossibility of using 

 the tuberculin test as a means of protection against bovine 



