Fermentation Products of Certain Mannitol- Forming Bacteria.*

The formation of mannitol in fermenting mixtures of plant, origin is now known to be due to a group of bacteria which act upon fructose and reduce this sugar to its corresponding alcohol. Mannitol-forming bacteria have been found in wine, sauerkraut, silage, canned goods, yeast, and cereal infusions. In some of t,hcse products such as sauerkraut and silage, their presence is not, objectionable, for it is probable t,hat t2hcy are among the chief microorganisms concerned in the natural souring and preservation of these materials. On the other hand, their presence and activities in the manufacture of wine, canned goods, yeast,, and but,yl alcohol arc the cause of much trouble and financial loss. It is in relation to the wine industry that this group of bacteria has received special study. The papers of Gayon and Dubourg (l), Miiller-Thurgau and Osterwalder (2), and others (38) furnish abundant evidence to prove the injurious nature of these microorganisms. The sugars are fermented to mannitol, acetic and lactic acids, and other products which result, in a sour wine of lowered alcoholic content. Fruit juices are, however, not the only source of these bacteria. Their presence on cabbage and corn as indicated by the formation of mannitol in sauerkraut and silage has been shown by Fcder (9), Nelson and Beck (lo), Brunkow, Fred, and Pel;erson (ll), and Dox and Plaisance (12). From these same sources mannitol-producing bacteria have been isolated by Plaisancc and Hammer (13), and Fred, Peterson, and Anderson (14). Smit (15), Van Steenbcrgc (IG), and Fred, Pctcr-