30 THE CANNING OF PEAS. 



Russell investigated the cau^e of swells in peas and, finding them 

 to be due to-bacterial infection as a result -of insufficient processing, 

 he recommended that the process be changed from ten and eleven 

 minutes at 230 F. to fifteen minutes at 242 F. The losses from 

 -\vells at this higher temperature were very small, and consequently 

 this temperature was recommended to the Wisconsin packers. 



In 1896 Prescott and Underwood b began the study of swelled and 

 sour corn and later turned their attention to sour peas. In February. 

 1901, they presented a paper before the American Canners' Associa- 

 tion on the cause of sour peas, and from their experiments determined 

 that the cause was underprocessing. As a result of these investiga- 

 tions, the} r recommended a process at 240 F. for thirty-five minutes 

 or 236 F. for forty minutes. The experiments reported at that time 

 became the basis of the process for a very large part of the pea 

 canning. 



Harding and Xicholson, c of the Xew York experiment station, 

 studied the swelling of peas, and gave a detailed description of the 

 organism to which it was ascribed. The} 1 found that a process at 

 240 F. for thirty minutes was effective in preventing swells, and 

 made such a recommendation for the prevention of losses. Other 

 writers have advocated a longer process at this temperature or a 

 higher temperature in order to prevent spoilage, and many factories 

 have adopted a heavier process some to the extent of greatly over- 

 cooking their goods. 



The writer processed a series of experimental goods for the purpose 

 of studying the various forms of spoilage, but with negative results. 

 All cans processed for fifteen minutes cr more at 240 F. were sterile, 

 and those processed at a lower temperature and for a shorter time 

 usually had a mixed infection. The resulting spoilage was so much 

 less than that given by other writers and generally found in practice 

 that it would seem unwise to make recommendations based upon one 

 year's work. 



The spoilage occurring before the peas enter the can is due to allow- 

 ing them to stand in piles, on the wagons or after thrashing, until 

 they heat and start fermentation. If the peas are kept moving from 

 the vine to. the can, the spoilage from this source is very small. If 

 hulled and thoroughly washed in cold water at short periods, they 

 may be kept for some time without appreciable spoilage. Peas held 

 on the vines longer than they should be, through accidents or over- 

 crowding, will not deteriorate to such an extent as to become unfit 

 for use if the vines are kept loose and the peas are well washed as 

 soon as hulled. The pods may become wet and even sticky before the 



" Wisconsin Agr. E.\i>. Sta. Rep., 1895, pp. 227-231. 



1 Prescott, S. C., and Underwood. L. M., Technology Quarterly, 1898, 11 : <>. 



c New York Agr. Exper. Sta., Geneva, 1903, Bui. 249. 



