1376 FOODS AND FOOD ADULTERANTS. 



be thoroughly cooked before the smaller ones begin to disintegrate. 

 The meat is then parboiled. 



PARBOILING. a 



Some houses vary the time of boiling from eight to twenty minutes, 

 owing to the size of the pieces of meat. Others boil for a definite 

 time twenty or thirty minutes, and in one ease one hour. 



CANNING. 



The parboiled meat is packed in cans, either by machine or by hand. 

 To each pound of meat is added from one- half ounce to 1 ounce of 

 some liquid, such as " soup liquor," in its natural state or after concen- 

 tration. In some cases salt is dissolved in this liquor for the purpose 

 of seasoning the meat, and sometimes a little molasses is added. The 

 tops are then soldered on the cans. 



PROCESSING. 



The cans are now placed in " process retorts" and heated by steam 

 under pressure. In some houses the cans are first heated for from 

 one and a half to two hours at the temperature of about 216 F., with 

 closed vent, when the heat is interrupted and the vents are opened to 

 allow the air to escape and then resealed. In other houses the cans 

 are heated for the same length of time with open vent, at the tempera- 

 ture of from 225 to 230 F. , after which the heat is interrupted and 

 the cans sealed. In both cases the cans are subjected to a second heat- 

 ing, the temperature varying in different houses between 235 and 

 250 F., and the time varying from one hour to an hour and three- 

 quarters. The cans are then left under a spray of cold water for 

 several hours, when they are washed, painted, and labeled. 



The above description contains the essential features of the pr< 

 as carried out by various canning establishments. The details of 

 manipulation vary in different houses. 



The most important modification is that described in a recent patent. 

 This consists in placing the cans, with open vent, in a vacuum appara- 

 tus and sealing them in vacuo. The cans are then carried slowly, by 

 means of an endless conveyer, through an oil bath whose temperature 

 is kept at about 240 F. , the speed being so regulated that they remain 

 in the oil bath long enough for processing. They are then transferred 

 automatically to other carriers and carried successively through a bath 

 of strong sodium carbonate solution, one of dilute sodium carbonate 

 solution, and one of water. They are then passed through a bath of 

 cold water and under a spray, after which they go to a sorting table 



a The reason for parlx>iling and its effect on the product are given on page 1389 et seq* 



