384 JAMES M. SHERMAN 



tile acids derived from the nitrogenous constituents of the 

 medium. 



Without going into details, it may be stated that of 16 samples 

 of American-made Swiss cheese purchased on the open market 

 all contained lactate-fermenting organisms in sufficient numbers 

 to be revealed in 0.000,001 gram, the highest dilution used. These 

 samples were representative of about the average run of domestic 

 Swiss cheese; only samples which had sufficient eye development 

 were taken, but the flavor varied from excellent to very poor. 



Thus it will be seen that we have succeeded in demonstrating 

 the presence of lactate-fermenting organisms in numbers consid- 

 erably greater than has been reported by other investigators. 

 Also, as will be shown later on, these bacteria have been isolated 

 directly from cheese without previous enrichment in some selec- 

 tive broth. 



Relation to previous work 



Concerning the discrepancies between the results of various 

 workers on this subject, we feel that these inconsistencies may 

 well be reconciled through the observations made in connection 

 with the work here reported. As has been noted, the reaction 

 of the lactate broth, as employed by Von Freudenrich and Orla- 

 Jensen and subsequent workers, is too acid for the best results. 

 The error which may be introduced by this factor is well illus- 

 trated by the following test made on a pure culture of a lactate- 

 fermenting organism from Swiss cheese: A broth culture one 

 week old as tested by the dilution method, using the regular Von 

 Freudenrich and Orla-Jensen broth (pH = 5.2), and another broth 

 of the same composition except that sodium lactate was substi- 

 tuted for the calcium salt. This broth had a reaction of pH = 

 6.8. The result of this test showed that, whereas the sodium lac- 

 tate broth gave a count of over 100,000,000 organisms per cubic 

 centimeter the number as indicated by the calcium lactate broth 

 was less than 1,000,000. 



Aside from the error introduced through the unfavorable re- 

 action of the calcium lactate broth, as it has been previously used, 

 there are apparently other factors which make the dilution method 



