Abstract
The growth rates of Salmonella oranienburg have been determined in four different basal media in which the water activity (a,v) was controlled by addition of salts and by addition of sucrose. In three complex media the lower limit for growth was between 0�94 and 0�95 aw but in a simple defined medium the limiting aw for growth was between 0�96 and 0�97. When an amino acid mixture containing proline and methionine was added to salt-adjusted simple medium, growth occurred at 0�96 aw' Subsequent addition of eight watersoluble vitamins extended the growth range to 0�95 aw'