UNITED STATES DEPARTMENT OF AGRICULTURE 



\ BULLETIN No. 1022 i 



Contribution from the Bureau of Plant Industry *~^± 



SL^'^TU WM. A. TAYLOR, Chief J&P*^&U 



Washington, D. C. ▼ February 3, 1922 



RELATION OF INITIAL TEMPERATURE TO PRES- 

 SURE, VACUUM, AND TEMPERATURE CHANGES 

 IN THE CONTAINER DURING CANNING OPERA- 

 TIONS. 



By C. A. Magoon and C. W. Culpeppeb, 

 Office of Horticultural and Pomological Investigations. 



Page. 



Canning problems 1 



Review of the literature 1 



Need for study of initial tempera- 

 ture in its relation to pressure and 



vacuum 4 



Methods and apparatus 6 



Theoretical pressures and vacuums- 9 



CONTENTS. 



Page. 



Experiments with distilled water for 



comparison 12 



Experiments with specific food ma- 

 terials 19 



Summary 50 



Literature cited 52 



CANNING PROBLEMS. 



If canned foods of uniform quality are to be produced, the vari- 

 ous canning operations must be placed upon a sound scientific basis 

 and the methods which are employed, so far as the nature of the 

 food substance will permit, must be carefully standardized. The situ- 

 ation calls for the elimination of the element of chance and the 

 abandonment of " rule-of-thumb " practices. It is equally impor- 

 tant that those factors which affect the cooking or processing of the 

 food after the can is sealed should be thoroughly understood. To 

 throw further light upon the matter of initial temperatures and their 

 bearing upon pressures, vacuums, and temperature changes during 

 and following the processing period, the present work was under- 

 taken, and it is hoped that the data presented herewith will con- 

 tribute to the solution of some of the canning problems. 



REVIEW OF THE LITERATURE. 



In an earlier paper the writers (8) 1 presented the results of pre- 

 liminary studies upon the fundamental factors affecting temperature 



1 Serial numbers in parentheses refer to " Literature cited " at the end of this bulletin. 

 70344°— 22 1 



