a). The characteristics of Lactobacillus plantarum

SUMMARY: The characteristics of 152 strains of lactobacilli were examined, and strains divided into three groups. Lactobacillus helveticus fermented inositol, sorbose, glycerol and rhamnose but not melibiose or raffinose, failed to grow in 4 yo bile salt, but gave EL positive Voges-Proskauer reaction and a rapid acid clot in Yeastrel glucose litmus milk (Y.G.L.M.). L. casei would not ferment these sugars, nor tolerate 4 yo bile salt, rarely gave a positive Voges-Proskauer reaction, but produced a rapid acid clot in Y.G.L.M. L. plantarum always fermented melibiose, usually raffinose and sometimes rhamnose, but did not ferment inositol, sorbose or glycerol. Strains of these species tolerated 4 yo bile salt but gave a negative Voges-Proskauer reaction and produced an acid clot in Y.G.L.M. only slowly. The identification of Lactobacillus helveticus, L. casei and L. plantarum has in the past been difficult and uncertain. These organisms have been confused with each other and with other species in the genus Lactobacillus. Bacillus casei a, y, y, and 6 were isolated from Emmenthal cheese and dif-ferentiated from each other by von Freudenreich & Thoni (1904) using pro