UNITED STATES DEPARTMENT OF AGRICULTURE 



jn-^^Vi. 



t BULLETIN No. 956 



Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOR, Chief 





Washington, D. C. 



August 17, 1921 



A STUDY OF THE FACTORS AFFECTING TEMPER- 

 ATURE CHANGES IN THE CONTAINER DURING 

 THE CANNING OF FRUITS AND VEGETABLES/ 



By C. A. Magoox and C. W. Culpki-i-ki:. Office of HorticnltHnil a)id J'ontolof/iral 



Investiiiations. 



CONTENTS. 



Page. 



Basis of the study 1 



Review of the literature - 



Methods and apparatus f' 



The steam retort T 



The brass fitting S 



Thermocouples 50 



The water bath 10 



Preliminary experiments 1" 



Distilled water lo 



Brine 11 



Sugar solutions 11 



Starch solutions IG 



Single-period proeessin;.; 17 



String beans 18 



Peas lil 



Lima beans 24 



Soy beans 'lo 



Asparagus L'S 



Page. 

 Single-period processing — Contd. 



Sweet corn 29 



Pumpkin 34 



Sweet potatoes 3G 



Tomatoes 30 



Cabbage 41 



Factors affecting the change of 

 temperature at the center of 



the can 42 



Intermittent processing 45 



String beans 45 



Sweet com 47 



Soy beans 48 



Sweet potatoes 50 



Factors influencing the rate of 



change nf temperature 50 



Summary 53 



LitiTature cited 55 



BASIS OF THE STUDY. 



Successt'ul preservation of foods by canning is clue primarily to 

 the fact that in the processing, or cooking, the bacteria and other 

 microorganisms which cause s]ioilage are destroyed. Since the 

 elimination of these microorganisms is dependent upon the use of 

 lieat as a sterilizing agent, it becomes of paramount importance to 

 know just what temperatures and processing periods will destroy 

 them. If uniformly good results are to be expected, a sufficient de- 

 gree of heat must penetrate to all parts of the can or jar, and must 



•The manuscript of this bulletin was sulunitted for publication on February 27, 1920; 



eircunistanecs of an iueidenlal eharaeter interferi-d with its early issue. 



■44!)00"— l-'l 1 



