Antimicrobial activity of Pseudomonas spp. against food poisoning bacteria and moulds.

The present study demonstrates the siderophore production of two strains of Pseudomonas fluorescens and two of Ps. chlororaphis. The antimicrobial activities of these strains were studied against Salmonella typhimurium, Staphylococcus aureus, Fusarium culmorum, F. oxysporum and Aspergillus niger. Despite equal siderophore activities with various Pseudomonas spp. as measured by the chrome azurol S assay, the study shows how siderophore activity does not correlate with the antibacterial activity against food pathogens or with the antimould activity against pathogenic moulds. Furthermore, the results illustrate how siderophores are able to act both as growth inhibitors and stimulators.