EXPERIMENT STATION BULLETINS. 



6:37 



The article by Larson, Cautwell and Hartzell (23) suggests to the 

 author of this bulletin that one explanation of the growth or lack of 

 growth of the spores of aerobes or anaerobes in canned foods may be 

 that the vegetable, fruit, etc., itself, or its extractives or various addi- 

 tions such as salt, sugar, etc., change the surface tension as well as other 

 physical characteristics of the medium thus changing the growth char- 

 acteristics of the organisms present. 



Then too, it was suggested to the writer that the presence of the 

 vacuum in a can may so serve to lower the surface tension as to influence 

 markedly the growth of living organisms therein. 



Tonney and Gooken (28) using the Morehead gas burette made 

 analyses of the gases from a number of cans of spoiled vegetables, fruit, 

 and fish ("swells'"). Their results for sx^oiled canned peas are given 

 in the following table: 



PER CENT 



The nitrogen which will be noted was obtained by difference and is 

 very high, is considered by the authors to be "a rough index of the amount 

 of proteid decomposition which has taken place, and as such has im- 

 portant bearing on the likelihood of the presence of ptomaines. In gen- 

 eral it may be said that nitrogen indicates putrefaction and carbon 

 dioxide indicates fermentation. * * * The presence of hydrogen, 

 * ■" * * is believed by the writers to be an especially valuable indi- 

 cation of jDtomaine producing processes." 



In the work on spoiled meats by K. George Falk, Emil J. Baumann 

 and Grace McGuire (IS) it was determined that all organisms experi- 

 mented with produced an increase in ammonia. B. proteus and B. para- 

 typhosus produced a marked increase of creatinin. Other organisms 

 produced definite changes in the protein present. The test for ammonia 

 the}' concluded could be used for determination of meat spoilage. 



METHOD OF PROCEDURE. 



In the summer of 1918 betAveen the first and twentieth of July . in 

 connection with an experiment in soils, thirteen lots of peas were picked, 

 weighed, and later canned in accordance with the Government methods 

 for cold pack canning. One lot was heated in steam; five were cooked 

 by the hot water bath method; and seven lots were processed in the 

 autoclave at fifteen pounds pressure. Lot A II X is the OTily one where 

 the canning was done the same day that the peas were picked. In lot 

 HWB I and A VI the peas were kept at room temperature over night. 



