112 S. A. KOSER AND W. W. SKINNER 



tococci, and pneumococci, in a period of time ranging from one 

 and one-half to two and one-half hours. Yeast cells were unaf- 

 fected after an exposure of forty-eight hours. 



Since these pressures are many times greater than those to 

 which the ordinary carbonated beverages are subjected, there is 

 the possibility that certain organisms may retain their ^dtahty 

 for a longer period. Several reports of the examination of car- 

 bonated beverages purchased in the open market have shown 

 that occasionally there are encountered considerable numbers 

 of microorganisms, including those indicative of pollution. Allen, 

 LaBach, Pinnell, and Brown (1915) report a sanitary survey of 

 the "soft drink" industry of Kentucky. Although carbonation 

 was found to cause a distinct reduction in the numbers present, 

 occasional high counts and the presence of Bad. coli were reported. 

 Stokes (1920) recently examined a great variety of "soft drinks" 

 and noted the frequent presence of Bad. coli in 10 cc. and 1 cc. 

 quantities, with an occasional occurrence in 0.1 cc. The plate 

 counts exhibited great variation, and while the majority of 

 samples yielded counts of less than 100 per cubic centimeter, 

 a few showed surprisingly high numbers. Gershenfeld (1920) 

 reports similar results. Young and Sherwood (1911) have 

 reported an experiment in which they determined the viability 

 of Bad. typhosum Bad. coli, and Enjthroh. ■prodigiosus in car- 

 bonated water to which lemon syrup had been added. Although 

 the typhoid bacillus showed a considerable reduction m numbers 

 after four hours exposure, a few viable cells were found after 

 ten days. Bad. coli and Erythrob. prodigiosus were found to be 

 somewhat more resistant than Bad. typhosum. 



In the present investigation chief emphasis has been placed 

 upon the colon-typhoid group for the purpose of determining the 

 length of time one may expect the various members of this group 

 to withstand the environment of the different types of commercial 

 carbonated beverages. 



The following organisms have been employed: Bad. coli 

 (fecal origin). Bad. paratyphosum B, and Bad. typhosimi. Also, 

 as a matter of interest, two common spore forms were included ; 

 B. mesentericus, and a putrefactive anaerobe of the Clostridium 

 sporogenes group. 



