Published online by Cambridge University Press: 15 May 2009
The skins of grains, all flours and all bread contain bacteria belonging to the group B. mesentericus. The cultural characters of six types of B. mesenteriucus isolated from grains and flour are given. Five of these were also obtained from ropy (or sour) bread. None of these five types can be identified as corresponding to the organisms isolated by earlier workers on rope. Rope, or sourness, does not result from the presence of these bacteria unless conditions are such as to allow of great development. The factors determining development of rope in bread are (1) degree of infection, (2) moisture, (3) temperature, ? (4) reaction, and (5) composition of the flour. A method of estimating the degree of infection of flours is given.