Pasteurisation of Milk for Butter-making. 513 



after running through the pasteurised milk than there was 

 from the unpasteurised milk. 



The creaming quality of the milk by the gravity process 

 decreased with an increased temperature before setting. 

 The whole milk averaged 4-08 per cent. fat. The skim milk 

 contained 3-08 per cent, fat when the whole milk was heated 

 to 180 0 before setting. Heating to 170 0 before setting produced 

 skim-milk testing 3*2 (? 2*2) per cent, fat ; heating to 175°, i*8 ; 

 to 160 0 , i-6; to 150 0 , ro; and to 140°, '88. Similar samples of 

 milk which were set at the ordinary temperature, without 

 heating, gave skim-milk testing an average of -51 per cent, 

 fat. All the lots were set for 24 hours in water which was at 

 a temperature of 40° to 45°. Tests with the creamometer 

 showed a very indistinct cream line in all the heated 

 samples, and especially was this so in those heated above 

 140 0 . 



The keeping quality of the butter and also of the skim- 

 milk was much improved by heating the whole milk to the 

 higher temperature before separating. Three boxes of butter 

 made in May, one from unpasteurised milk, one from milk 

 heated to 140 0 , and another from milk heated to 190, were 

 kept at an average temperature of about 55 0 until the 17th 

 August. These boxes were examined from time to time, and 

 it was found that the box made from milk heated to 190.' 

 held its flavour best and was quite as good in other respects. 

 On the 1 7th August the numerical estimates for flavour were 

 38, 35, and 32 (max. 45), in the order of decreasing tempera- 

 ture at the time of separating. 



The moisture content of the pasteurised butter was 1077 

 per cent, one per cent, less than the sample of butter made 

 from unpasteurised milk. 



The Professor of Dairy Husbandry at the College, Professor 

 H. H. Dean, draws the following conclusions from these 

 results. Good butter can be made from milk and cream 

 without pasteurisation ; but pasteurisation of the milk or 

 cream tends to produce uniformity of product and adds to the 

 keeping quality of the butter. The higher the temperature 

 of the milk, the better is the keeping quality of the milk and 

 butter, but the greater is the expense for heating and cooling. 



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