100 ILLINOIS STATE DAIRYMEN'S ASSOCIATION 



such objections was to some extent lack of knowledge in regard 

 to pasteurization. Some were of the opinion that the cost of 

 pasteurizing, including fat losses in the butter milk, would be 

 enormous. Experiments conducted at the Iowa Experiment Sta- 

 tion reports of which is published in the Iowa Bulletin No. 156 

 indicate that fat losses in the butter milk are greater from raw 

 cream when compared with that of sweet cream pasteurized. If 

 the cream however, is pasteurized in sour condition then the per 

 cent of butter fat lost in the butter milk is slightly greater from 

 the pasteurized than from the raw cream. 



The cost of pasteurization in a small plant, figuring cost of 

 steam, water, interest and depreciation on investment, insurance, 

 etc., may be estimated for the flash method at about 0.6c per 

 pound of butter fat figuring the fat content of the cream at 30 

 per cent. By the vat method this figure will be reduced to about 

 0.45c per pound of butter fat. For a large creamery these fig- 

 ures will be slightly reduced, a further reduction in cost may be 

 made if pasteurization can be done with exhaust steam. Bo wen 

 (Bull. 85 B. A. I.) gives the cost of pasteurizing one gallon of 

 milk at 0.313c and for one gallon cream at 0.634c but these fig- 

 ures include only cost of steam and water. 



As this gathering largely is composed of men interested in 

 the manufacture of dairy products some of the practical prob- 

 lems evolved in the process of pasteurization will naturally be 

 of some interest. In taking up such problems for discussion it 

 will be convenient to distinguish between the operation in the 

 whole milk creamery and in the gathered cream plant. 



Pasteurization in the Whole Milk Plant : This may be done 

 in two ways, either the milk may be pasteurized before separa- 

 tion or the cream pasteurized after separation. By the former 

 method the flash heat system is to be preferred the milk being 

 heated to a temperature of from 180 degrees F. to 185 degrees 

 F. and cooled to about 80 or 90 degrees F. before entering the 

 separator. The cream is then cooled to ripening temperature. 

 By the latter method the cream is pasteurized after skimming 

 and may be accomplished either by employing the flash heat or 

 the prolonged heat or vat method. The cream by the latter 



