116 Dairy Bacteriology. 



conditions that permitted of the formation of the scalded 

 layer. This is a point of great practical importance in the 

 treatment of milk and necessitates the use of machinery 

 that will prevent the formation of this surface film. It 

 follows, therefore, from these results that a temperature of 

 140 F. can be used if advisable, although higher temper- 

 atures are not inadmissible. 



Sanitary advantages of pasteurized milk. Not only does 

 pasteurized milk keep longer and is also free from specific 

 disease bacteria, but its use has been of utmost importance 

 in checking infant mortality from diarrhoeal disturbances. 

 This is shown in the diminished death rate in children's 

 hospitals, and is again exemplified on a large scale in the 

 results that have been obtained in New York City through 

 the liberality of Nathan Strauss, who, for several years, 

 has furnished the poor children of that city with pasteurized 

 milk. Since the introduction of this milk, the death rate 

 of those under five years of age has dropped over ten per 

 thousand living persons, a condition which is explicable 

 in large measure to the use of a relatively germ-free milk. 



Pasteurized milk should be consumed within twenty-four 

 hours if it is used by children. If left under conditions 

 favorable to germination, bacterial growth will go on, and 

 it has been shown that the type of fermentation produced 

 may sometimes be deleterious. 1 



High vs. low temperature pasteurization. The limit 

 which has been most generally employed has been the 

 maximum at which a cooked flavor did not appear, and in 

 practice this has been 155 F. for a period of exposure of 

 twenty minutes. Under these conditions, pasteurization 

 is efficiently and thoroughly performed, but the applica- 

 tion of this degree of heat to milk results in a diminution 



Fltlgge, Zeit. f. Hyg., 1894, 17: 272. 



