THE PASTEURIZATION OF MILK 



in heating the milk in any good form of pasteuriz- 

 ing apparatus, and then pouring it, while hot, into 

 bottles which have just emerged in a hot condition 

 from this sterilizing apparatus. The heat which 

 is usually lost in cooling the hot bottles is in this 

 way saved. Since, however, the bottles must in 

 any case be cooled, it can be seen that the cooling, 

 which usually takes place slowly in the air when 

 washed bottles are stored in the ordinary way, 

 must now be accomplished rapidly in order to re- 

 duce the milk to the proper temperature in the 

 time required. This necessitates the use of ice 

 water or brine refrigeration, and since the volume 

 of glass used equals the volume of the milk, dou- 

 ble the amount of cooling medium is required than 

 when only the milk is cooled. 



Experiments were made by Ayers and Johnson 

 in which the heated milk in bottles received a pri- 

 mary cooling by means of blasts of air at ordinary 

 temperatures. These experiments indicated that 

 a considerable economical saving of cooling medium 

 thus could be effected. Completing the cooling by 

 means of blasts of chilled air produced satisfac- 

 tory results. The fact that the cooling process 

 required a long time seemed to produce no harm- 

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