UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 420 



Contribntioii from the Boreau of Animal Indnatry 

 A. D. MELVIN, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



October 27, 1916 



COOLING HOT-BOTTLED PASTEURIZED MILK 

 BY FORCED AIR 



By 



S. HENRY AYERS, JOHN T. BOWEN, and 

 W. T. JOHNSON, Jr., Dairy Division 



CONTENTS 



Page 



Introdnctioii 1 



Description of Experimental Apparatus . 2 

 Description of Instruments and Method 



of Recording Data 3 



Relative Rate of Cooling of Milk and 



Water 5 



Relative Rate of Cooling with Still Air 



and Forced Air 5 



Results of Cooling by Means of Forced 



Air 9 



Temperature Yariations in Quart Bottles 



of Milk and Water Under Varying 



Conditions 19 



Page 

 Cost of Cooling by Means of Cold Ont- 



sideAir 23 



Effect of Slow Cooling on the Bacterial 



Flora of Milk after Pasteurization . . 26 

 Effect of the Process on the Cream Line 



and Flavor of Milk 30 



Experiments in Heating Bottled Milk by 



Forced Air 32 



General Summary 3S 



Conclusion 37 



WASHINGTON 



GOVERNMENT PRINTING OFFICE 



1916 



