STERILIZATION OF MILK. 151 



even to 212 F., then cooled to about 86 F., and good 

 rennet added in larger quantities than usual, distinct 

 symptoms of coagulation will appear, although much slower 

 than ordinarily. Not only are the albuminoids of the milk 

 changed by a stronger heating, but the milk sugar also 

 shows the influence of the heat. If a temperature of 185 

 to 200 F. acts on the milk for some time or at intervals, 

 it will be easily noticed that it assumes a brown coloration ; 

 this occurs through a formation of caramel in the milk, its 

 milk sugar being partly decomposed. 



If the heating is carried farther, the symptoms men- 

 tioned become still more noticeable, and at the same time 

 the cooked taste, which was only slight by heating to about 

 167 F., becomes more pronounced. At 266-300 F. a 

 coagulation of casein takes place, according to Hammar- 

 sten, in a manner chemically identical with the coagula- 

 tion through the addition of rennet. 



The sterilization through heating is in practice con- 

 ducted in two ways: 1, ty foiling under pressure, and 2, 

 ty ordinary foiling. 



The ormer method was introduced into practice by 

 Nageli, who, at the Dairy Exposition in Berlin in 1879, 

 published his experiences with the same. As the foremost 

 spokesman of this method in practice, E. Scherif, in Wen- 

 disch Buchholtz (Berlin), has made himself known, and 

 ScherfP s milk has of late often been spoken of. Ac- 

 cording to his method of procedure the newly-drawn milk 

 is poured into glass bottles, which are stoppered, and then 

 heated under pressure at 248 F. (120 C.) for one to two 

 hours. This method is old, and has long be_en_known in 

 science. The new in Scherff s meth 



