SKIM MILK AND BUTTERMILK 135 



ing: (i) the dilution of the skimmilk by condensed 

 steam; (2) the cylinder oil carried into the milk where 

 exhaust steam is used; and (3) the trouble from ex- 

 cessive foaming. 



There are pasteurizers upon the market provided with 

 oil traps which have been reported as eliminating the 

 trouble from cylinder oil. The trouble from foaming can 

 also be largely eliminated. Various so-called "foam kill- 

 ers" have been placed upon the market which have been 

 more or less successful in obviating this trouble. 



Fig. 31 illustrates a method of handling skimmilk 

 which prevents, to a great extent, the difficulty usually ex- 

 perienced from foam. 



The pasteurizer may be placed on top of the skimmilk 

 tank and the pasteurized skimmilk allowed to flow 

 through a pipe which runs to within an inch or an inch 

 and a half of the bottom of the tank. A pipe so placed 

 will tend to destroy a portion of the foam formed in the 

 heater. The tank is of ample size to hold the foam not 

 thus destroyed, which, during the early summer, is quite 

 considerable. The larger the tank the less trouble will 

 be experienced from the foam. 



While the trouble from oil and foam may be largely 

 obviated, the dilution resulting from the condensed steam 

 must always stand as an objection to the direct method of 

 pasteurizing skimmilk. 



Indirect Method. Skimmilk can be pasteurized with 

 the "continuous" style of pasteurizers in the same way as 

 cream. This method is now employed in many creameries 

 and should be adopted wherever possible. The extra cost 

 of a pasteurizer is more than compensated for in doing 

 away with the objections inherent in the direct method of 



