Pseudomonas fragi is a psychrophilic, Gram-negative bacterium that is responsible for dairy spoilage. Unlike many other members of the genus Pseudomonas, P. fragi does not produce siderophores. Optimal temperature for growth is 30 ðC, however it can grow between 0 and 35 ðC. Based on 16S rRNA analysis, P. fragi has been placed in the P. chlororaphis group.