196 ILLINOIS STATE DAIRYMEN'S ASSOCIATION 



Experiments made frequently have shown that low tem- 

 peratures will greatly retard the growth of most germs, and that 

 cream quickly cooled will keep sweet much longer than when 

 it is allowed to cool gradually. The practice of adding warm 

 cream to cream that has been previously cooled is recognized 

 as being extremely undesirable, because warm cream raises the 

 temperature of the whole mass sufficiently to start the dormant 

 bacteria to activity, causing them to multiply rapidly, producing 

 large amounts of acid and also undesirable fermentations before 

 the cream is again cooled to a point where their growth is 

 checked. Warm cream should be thoroughly cooled before it 

 is added to the cold cream. 



Low Temperatures. 



From these facts it appears that the most practical means 

 at the disposal of the dairymen for checking bacterial action — 

 the spoiling of cream — lies in the universal application of low 

 temperatures in handling the cream. The most satisfactory 

 and practical means of securing these desirable results has been 

 by the use of some form of cooling tank. 



Recognizing the great importance of devising a cooling 

 tank that will be at once cheap, practical and efficient, the de- 

 partment of dairy husbandry of Nebraska, in co-operation with 

 Profs. G. L. McKay and F. W. Bouska, of the American 

 Creamery Butter Manufacturers' Association, have spent much 

 time investigating this problem. An effort has been made to 

 perfect a tank that would be both effective and convenient. Such 

 a tank must be substantially made of good insulating material 

 and able to stand up under hard usage. It must have a tight 

 cover in order to prevent loss of efficiency due to exposure of 

 the cooling water to the air. The pipe through which the cool- 

 ing water enters should discharge near the bottom of the tank, 

 and the overflow near the top and at the opposite end, and 

 should be of such size that there will be no danger of water 

 rising above the tops of the cans. With these general require- 

 ments in mind the committee, together wjth the co-operation of 

 representatives of local creameries, devised, constructed and ex- 



