PASTEURIZATION. 175 



deal with we must pasteurize the cream. If we had 

 first class dairymen and were positive that all the 

 cows were healthy, the help employed free from 

 communicable diseases and the water pure, we might 

 dispense with pasteurization altogether. However, 

 as we do not have this ideal condition at present it 

 is certainly safer to pasteurize all cream for butter 

 making. 



222. Preparation of cream for pasteurization. All 

 cream whether sweet or sour must be thoroughly 

 mixed before being put into the pasteurizing ma- 

 chine. Unless the butter fat is evenly distributed 

 through the cream the result will not be satisfactory. 

 When cream is sour and lumpy when received it 

 should be strained through a wire; strainer and after- 

 ward thoroughly stirred in order to break up all 

 clots and break up the coagulated casein into the 

 smallest possible particles. If this is not done the 

 clots of casein when heated will curdle and form 

 hard granules enclosing fat globules. Some of these 

 granules of casein and butter fat will go into the 

 buttermilk when the cream is churned, and some of 

 them go into the butter. These specks of casein in 

 the butter may cause the butter to decompose more 

 readily and may also be the cause of reduced price 

 obtained for butter. If an intermittent pasteurizer 

 is used in pasteurizing lumpy cream, the granules 

 of casein produce a sediment in the bottom of the 

 pasteurizer. 



223. Mixing sweet and sour cream. When a cream- 

 ery receives a large quantity of both sweet and sour 

 cream, these should not be mixed unless it is neces- 



