Studies of Commercial Sauerkraut with Special Reference to Changes in the Bacterial Flora during Fermentation at Low Temperatures

The fermentation of cabbage is a spontaneous one, and the manufacturer of sauerkraut must take the undesirable microorganisms along with the desirable ones. Because of this chance inoculation, there is a wide variation in the quality of sauerkraut. A large variety of organisms is introduced with the green plant tissue when this is placed in the vats. Many of the forms on plants can not survive under the conditions in the vat, while others find the conditions very favorable and increase to enormous numbers. Changes in oxygen tension, hydrogen-ion concentration, and fermentable carbohydrate bring about conditions which for a few days are favorable for certain kinds of bacteria, but within a few days more these conditions may change and become unsuitable for that particular kind of microorganism. A new flora better adapted to the new conditions may come to the front and persist for a shorter or longer period of time. Although the general character of the fermentation is similar in all vats, no two are exactly the same. The extensive research which has been made on silage shows clearly that the souring of plant tissue is the result of the combined action of many types of microorganisms. Although there are decided differences between the formation of silage and of sauerkraut, the inain outlines of the two processes are the same and many of the same bacteria are found in both fermentations.