UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 420 
Contribution from the Bureau of Animal Industry 
A. D. MELVIN, Chief 
Washington, D. C. 
PROFESSIONAL PAPER 
October 27, 1916 
COOLING HOT-BOTTLED PASTEURIZED MDLK 
BY FORCED AIR 
By 
S. HENRY AYERS, JOHN T. BOWEN, and 
W. T. JOHNSON, Jr., Dairy Division 
CONTENTS 
Introduction 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 Variations in Quart Bottles 
of Milk and Water Under Varying 
Conditions 19 
Page 
Cost of Cooling by Means of Cold Out- 
side Air 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 80 
Experiments in Heating Bottled Milk by 
Forced Air 32 
General Summary 35 
Conclusion 37 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1916 
