PRODUCTION OF PINK SAUERKRAUT BY YEASTS 267 



acid bacteria isolated from plant tissue are not retarded in the 

 least by this concentration of salt. In the presence of larger 

 amounts of salt (5.5 per cent), all of the rod forms of lactic bacteria 

 are injured. A concentration of not more than 2 to 4 per cent 

 of salt would not seriously retard the growth of the yeast and 

 would favor its production of pigment. 



EFFECT OF HIGH ACID FORMING BACTERIA ON THE PRODUCTION 

 OF PINK SAUERKRAUT 



The use of bacteria which would ferment the sugars of the 

 cabbage juice rapidly naturally suggests itself as a means of 

 combating the growth of pink yeasts. If great numbers of acid 

 producing bacteria are seeded in the raw cabbage then it is pos- 

 sible that they will so dominate the fermentation that the wild 

 yeasts will not be able to exert any well defined effect on the 

 kraut. The fallacy of this assumption, however, is clearly seen 

 from the results of table 4. As in the preceding tests large per- 

 colators with 1000 grams each of raw cabbage were used. The 

 data include the results of four separate tests carried out at 

 different times. In every case before the end of the fermentation 

 period the cabbage to which acid was added or which was inocu- 

 lated with high acid-producing bacteria turned pink. Appar- 

 entlj^ the high acid production which followed inoculation favored 

 the gro^\•th of pink yeasts. Direct microscopic mounts made 

 from this pink sauerkraut furnished support for this statement 

 "VNTien opened, the inoculated kraut showed great numbers of 

 yeasts. Some idea of the rate of acid formation may be gained 

 from the figures in this table. In the early stages of fermentation, 

 without exception, the kraut seeded with aciduric bacteria showed 

 a much greater quantity of acid than the control kraut. This 

 difference is especially noticeable in the titration figures of the 

 first four or five days. After eight days, conditions changed 

 and before the end of the fermentation the control krauts were 

 far more acid than the inoculated krauts. Culture 124-1 which is 

 a high acid former from pentoses and other sugars is especially 

 favorable for the development of the pink yeasts. On the 

 other hand the non-pentose fermenter Bad. lactis-acidi which 



