Interactions between fish isolates Pseudomonas fluorescens and Staphylococcus aureus in dual-species biofilms and sensitivity to carvacrol

Biofilm formation is a frequent source of contamination of food products, which results in significant economic losses through microbial spoilage and poses serious health concerns. Little is known about the fate of Staphylococcus aureus in the dual-species biofilms with Pseudomonas fluorescens an important spoiler commonly found in aquatic products. This study evaluates the interactions between mono- or dual-species biofilms formed by P. fluorescens and S. aureus, as well as the sensitivity of the two tested strains to carvacrol. The biofilm cell population, expolysaccharide production, biofilm structures of P. fluorescens as mono- and dual-species with S. aureus at ratios of 1:1 and 1:0.01 were investigated with different concentrations of carvacrol (0, 0.4, 0.8 and 1.6 mM) in fish juice at 30 °C. The results show that the biofilm cell population of S. aureus in the dual-species was significantly lower (p