Abstract: The invention comprises a culture medium and method for distinguishing bacteria of Salmonella species from other gram-negative bacteria, especially those belonging to the family Enterobacteriaceae. It is based on the ability of salmonellae to utilize melibiose, mannitol, and sorbitol and convert them into acids, together with a chromogenic substrate used for identifying .beta.-galactosidase. Other bacteria of the family Enterobacteriaceae, most of which are .beta.-galactosidase-positive, appear as brown, blue, or green colonies, depending on the chromogenic substrate used. Apart from Salmonella species, other .beta.-galactosidase-negative bacteria, such as Proteus species, appear as colorless colonies. Salmonellae can be identified directly on the culture medium after incubation, by their characteristic bright red color.