Thirty-sixth Annual Convention 937 



perature as high as 185 degrees in the one heating, there is grave 

 danger of injuring the quality, as some portions of that cream 

 must necessarily reach a temperature of over 200 degrees P., 

 that is, the portions of the cream that are next to the plate of 

 the pasteurizer will reach that temperature. The action of this 

 excessive heat on the fat and other constituents, no doul)t, im- 

 parts to the cream had flavors that are transmitted to the hutter. 

 I am not opposed to pasteurization, either high or low. I main- 

 tain, however, that the process when rightly done is a very delicate 

 operation. If cream is to he heated to a high temperature, I am 

 tirmly convinced that we should use two pasteurizers in the pro- 

 cess of raising the temperature to 185 degrees. In the first pas- 

 teurizer, the temperature should reach from 110 to 120 degrees. 

 This increases the fluidity of the cream so that it can be heated 

 in the second pasteurizer without using such excessive heat. Where 

 a method of this kind is used, the exhaust from the last pasteurizer 

 can he attached to the flrst for bringing up the temperature to 110 

 or 120 degrees, as desired, thus economizing in the use of steam. 



I notice that some of our large creameries are using this method 

 and getting excellent results. 



Where pasteurization is done in the vat, as is practiced now 

 in many creameries, a temperature of 150 to 155 degrees is suffi- 

 cient, especially if cream is to be held 15 to 20 minutes at this 

 temperature. I have also seen excellent results from this method 

 of operation. 



I have been scoring butter for some time in experiments that 

 are being conducted at Perdue University. In the last scoring, 

 I observed a difference of about three points in favor of j^asteuri- 

 zation as against butter made from the same cream without being 

 pasteurized. I understand that the cream was very sour in both 

 cases. The temperature in this particular case was IGO degrees. 



About twelve years ago I conducted a series of experiments 

 at Iowa State College with sour cream, with the intention of pub- 

 lishing a bulletin on the final results. Knowing that only a small 

 portion of the milk sugar was converted into acid during the 

 souring of creamj I took up the method of neutralizing this acid 



