Inhibition of quorum sensing signals in foodborne pathogens by different plant extracts

This study aimed to determine the antimicrobial, antibiofilm and quorum sensing inhibition (QSI) properties of different herbal extracts and the usability of the samples for biofilm control on surfaces used in the food industry. Firstly, extraction was made from the pulp, an industrial waste of Punica granatum L. (pomegranate) fruit with different solvents. Antimicrobial activities, MIC and MBC values of samples on foodborne pathogens (L. monocytogenes, S. aureus, B. cereus, E. coli O157:H7, P. aeruginosa and C. sakazakii) were determined. Antibiofilm analyzes of the samples in polystyrene-based microplates were performed by prevention of biofilm formation and removing biofilms, and L. monocytogenes, S. aureus, P. aeruginosa and C. sakazakii were used in the analyses. Then, the anti-biofilm forming activity of samples on L. monocytogenes and C. sakazakii were analyzed on stainless steel and glass surfaces. P. aeruginosa ATCC 27853 and C. violaceum ATCC 12472 strains were used to assess the QSI activity of the samples. The results showed that the antimicrobial (24-37.5 mm) and antibiofilm (64-80%, inhibition on polystyrene, stainless steel and glass surfaces) activities of pomegranate waste extract (B) prepared with methanol-acid-water on the investigated pathogens were higher than other pomegranate waste extracts. Rose oil and rose absolute samples have been shown to be successful in controlling L. monocytogenes and C. sakazakii biofilms on surfaces. The samples inhibited swarming motility by 61-77%, swimming motility by 38-86%, protease activity by 53-86% and pyocyanin production by 38-55% on P. aeruginosa ATCC 27853 strain. In addition, the suppression rate of the samples in violaceum production on C. violaceum ATCC 12472 strain was found to be between 35-68%. It has been revealed that among the researched samples, B extract, rose oil, rose absolute and punicalagin have the potential to be used in natural disinfectant formulas.