Contribution from the Bureau of Plant Industry 
WM. A. TAYLOR, Chief 
| Washington, D.C. Vv February 3, 1922 
RELATION OF INITIAL TEMPERATURE TO PRES- 
| SURE, VACUUM, AND TEMPERATURE CHANGES 
| IN THE CONTAINER DURING CANNING OPERA- 
_ TIONS. 
By C. A. MAcoon and C. W. CULPEPPER, 
Office of Horticultural and Pomological Investigations. 
CONTENTS. 
Canning problems_---_~~~..--__-_ 1 | Experiments with distilled water for 
Review of the literature___________ aft COMP ATISO Ness how 12 
Need for study of initial tempera- Experiments with specific food ma- 
ture in its relation to pressure and PERTAINS (aehie M AER oye E oane 19 
TATA 2 i 4 Summa SS ee ee 50 
Methods and apparatus___________ Gra laiteratures cited == ste eee 52 
Theoretical pressures and vacuums_ 9 
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. 
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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 
