BULLETIN OF THE 



No. 196 



Contribution from the Bureau of Chemistry, Carl L. Alsberg, Chief 

 May 29, 1915. 



(PROFESSIONAL PAPER.; 



METHODS FOLLOWED IN THE COMMERCIAL 

 CANNING OF FOODS.^ 



By A. W. Bitting. 



CONTENTS. 



Page. 



Modem factory equipment and methods 1 



Containers 10 



The label 12 



Use of the term "canned".: 13 



Spoilage 13 



Effect of heat and cold 14 



Cost of canned foods compared with fresh ... 15 



Extent of the canning industry in the United 



States 16 



Packing seasons 16 



Experimental work 19 



Detailed consideration of the various prod- 

 ucts 21 



MODERN FACTORY EQUIPMENT AND METHODS. 



METHODS OF STERILIZATION. 



Sterilization may be accomplished by heat below, at, or above the boiling tem- 

 perature, depending upon the length of time the heat is applied and the number of 

 applications made. It is not practicable to sterilize all foods in the same way because 

 of injury to quality or prohibitive expense. Sterilizing below the boiling point is 

 feasible only for a few products, principally fruits, and then is advisable only when 

 it is desired to preserve a very fine appearance. This may be accomplished above 

 165° F. by maintaining the temperature for a longer time than when boiling, or by 

 repeating the operation on two or more successive days. The object is to prevent 

 bn-aking the tissue and loss of juices from the fruits by excessive heat. This method 

 of sU-rilization has been applied experimentally and in private canning with grati- 

 fying results, but it involves m mucli time and labor tliat it is not uk('<1 commercially 

 except in a limiU;d way. Suffic-ient work has not been done to say definitely what 

 pnKhictfl f;an bfjst be treated in this way nor wliat t<'i)ip<'ratures ar<^ Ix-st suited for 

 different ffxxls. It has been u«e<l chiefly with foods in glass, though (Mpially satis- 

 factory resultw are obtain<'d with foods in tin. 



Ox>king at boiling temp<'ratur<! is practic(!d with nearly all fruits, as tlie j^rcnns 

 pre8<-ntare raHJly destroyed. Most of the fruits are processed for from 12 to 25 rniiuil<!H. 



'A rpvLslon of liiiroau of (^hemUtry Ddllolin 1.11, oiiliir(;ing upon certain phases of Iho miiiiufactiiriMg 

 pTflCmiMr■^, and lnc<rt-pfjratlnK a summary of the results of Iho experimental work of the sca.son of 1912 and 

 1913, KInco the Information Includes only (he methods of commercial cuiniing, It Is of no Inl crest lo the 

 borne canner. I'rejM^nlatlon of the tnulo [iractlce.s docs not lni[)ly an Indorsemoiit by the liurouu of 

 Chomtetry. Preparwl by A. W. {3ltlln|{ while focxl technologist of the bureau. 

 7OT.VJ*— Bull. 19ft-15 1 



