Quorum quenching and antimicrobial potential of natural compounds against foodborne biofilm-forming bacteria

Background: Biofilm formation represents a major challenge for food safety, contributing to persistent contamination, compromised process hygiene, and increased antimicrobial resistance.Because quorum sensing (QS) regulates biofilm development, interference with QS signaling (quorum quenching [QQ]) has emerged as a promising strategy for biofilm control.Aims: This study aimed to evaluate the biofilm-forming capacity and QS (N-acyl homoserine lactones [AHL] and autoinducer-2 [AI-2]) activity of foodborne bacterial isolates and to assess the antimicrobial and QQ potential of selected natural products under in vitro conditions.Methods: A total of 109 bacterial isolates from dairy processing lines were assessed for biofilm formation using a 96-well microtiter assay.QS activity was detected using indicator microorganisms for AHL and AI-2 signaling.Selected natural products (1 mg/mL) were screened for antimicrobial and QQ activity, with QS inhibition evaluated independently of growth suppression.Results: A total of 89% of the isolates were classified as strong biofilm producers, with Bacillus and Pseudomonas species predominating.Plant-derived extracts and natural products, including Calendula officinalis, propolis, nisin, and Hypericum perforatum, exhibited measurable antimicrobial and antibiofilm activity.Propolis and C. officinalis reduced QS-associated biofilm responses independently of growth inhibition, indicating potential QQ activity. Conclusion:These findings highlight the potential of natural extracts as eco-friendly alternatives to chemical disinfectants in food processing environments. zetDayanak: Biyofilm oluumu, gda gvenlii asndan kalc kontaminasyona, proses hijyeninin bozulmasna ve artan antimikrobiyal dirence yol aan nemli bir sorundur.Biyofilm geliimini dzenleyen quorum sensing (QS) sisteminin engellenmesi (quorum quenching [QQ]), biyofilm kontrol iin umut vadeden bir yaklamdr.Amalar: Bu almada, st rnleri proses hatlarndan izole edilen bakteri izolatlarnn biyofilm oluturma kapasiteleri ile QS'e bal (N-asil homoserin laktonu [AHL] ve otoindkleyici-2 [AI-2]) sinyal aktivitelerinin deerlendirilmesi ve seilmi doal rnlerin in vitro koullarda antimikrobiyal ve QQ potansiyellerinin belirlenmesi amalanmtr.Yntemler: Toplam 109 izolatn biyofilm oluumu 96 kuyucuklu mikroplak yntemi ile belirlenmi, QS aktivitesi indikatr mikroorganizmalar kullanlarak saptanmtr.Doal rnler (1 mg/ mL) antimikrobiyal ve QQ aktiviteleri asndan tarama dzeyinde incelenmi