Antimicrobial effect of benzoic and sorbic acid salts and nano-solubilisates against Staphylococcus aureus, Pseudomonas fluorescens and chicken microbiota biofilms

The objective of this study was to evaluate the antimicrobial effects of benzoic and sorbic acid salt and their nano-solubilisates against planktonic and biofilm cultures of Staphylococcus aureus, Pseudomonas fluorescens and chicken microbiota. The antimicrobial activity was affected by the particle size of the organic acid antimicrobials, the Gram-strain, and the type of culture (planktonic or biofilm) used. The organic acid nano-solubilisates were significantly (P < 0.05) more effective compared to their organic acid salt counterpart with respect to both planktonic and biofilm cultures. However, biofilms of Staphylococcus aureus, Pseudomonas fluorescens and chicken microbiota were significantly (P < 0.05) more resistant to both organic acids salts and nano-solubilisates compared to the planktonic cultures. The physicochemical properties of the organic acids antimicrobials was assessed using particle size analysis, Fourier Transform Infrared (FTIR) spectroscopy and Atomic Force Microscopy (AFM) analyses. Biofilm formation after 24 h was quantified using a crystal violet assay and the minimum inhibition concentration against planktonic and biofilm cultures was also determined. The unique physiochemical properties of these nanomaterials may allow for potential applications in the development of naturally derived antimicrobial active packaging materials.