192 CANADIAN DAIRYING. 



series of experiments conducted at the Ontario 

 Agricultural College. The chief results of this work 

 are summarized as follows in Bulletin 117 : 



" i. The milk, as ordinarily delivered at a creamery, may be 

 pasteurized. The milk used in these experiments was largely 

 furnished by the patrons who had but ordinary facilities for 

 taking care of it. In the winter we received our milk but three 

 times a week ; in summer it is delivered daily. 



" 2. On but two occasions was the acidity of the milk over 

 .2 per cent. The acidity averaged about .17 per cent. There 

 is danger of the milk coagulating when heated, if it contains 

 more than .2 per cent of acidity. 



"3. It was noticed that the lots heated from 185 to 195 

 degrees produced more foam than those heated to the lower 

 temperatures of 140 to 160 degrees. This was most noticeable 

 in the samples heated to 195 degrees. At 185 degrees the foam 

 was not sufficient to cause much trouble in handling. 



"4. The use of ten to fifteen per cent, of culture in the 

 pasteurized cream enabled us to ripen the cream without any 

 difficulty. The culture was a lactic acid bacillus. 



" 5. Pasteurization of milk at 185 degrees, and the use of a 

 pure culture is the best method of securing uniformity, keeping 

 quality, and the mild flavor requisite for export butter. 



" 6. The cooked flavor, which was present in the butter made 

 from milk heated from 185 to 195 degrees, usually disappeared 

 at the end of about two weeks. In one or two lots heated to 

 195 degrees the cooked flavor remained for some time. There 

 is apparently no danger of cooked flavors on butter made from 

 milk pasteurized at 185 degrees, at the end of two weeks, or by 

 the time it would reach the British markets. 



"7. The species of bacteria present in the milk when the 

 cows were kept in the stable, were very undesirable. Many 

 putrefactive and fecal bacteria were present, hence the necessity 

 of keeping the stable walls and rafters well cleaned. A good 

 coat of whitewash increases the amount of light, and gives a 

 general clean effect to the stables. 



