Identity and Origin of the Malty Aroma Substance from Milk Cultures of Streptococcus Lactis var. Maltigenes

The development" of the malty defect in dairy products appears to be the result of a peculiar bacterial fermentation about which little is known.The organism most commonly associated with this defect is Streptococcus lactis var.maltigenes.This organism appears to differ from S. lactis only in its ability to produce a malt-like aroma in milk (3, 4).Virtanen and Nikkil~i (12) have described a "malt coccus" which they isolated from malty butter cultures.Although this organism differs from S. lactis var.maltigenes in its biochemical characteristics, it is noteworthy that these workers found it produces a considerable amount of acetaldehyde in milk and believe this compound to be responsible for the malty aroma.Simulation of the malty defect in normal butter cultures by addition of acetaldehyde seems to have led them to this conclusion.