Work

Evaluation and comparison of the effects of different exogenous photosensitizers under high irradiance blue light on Listeria monocytogenes

Year: 2026

Type: article

Abstract: Photodynamic inactivation is an innovative antimicrobial treatment that can be enhanced using high-irradiance blue light (HI-BL) in combination with exogenous photosensitizers. Hence, this study compares the effects of four photosensitizers (curcumin, berberine, quercetin, and capsaicin) under HI-BL on Listeria monocytogenes (Lm), including their antimicrobial activity, gene expression regulation, anti-biofilm efficacy, and potential application in smoked salmon. Berberine-mediated HI-BL reduced Lm viability by 2.9 log CFU/mL within 1 min 15 s, corresponding to 25 J/cm 2 . In the biofilm model, Lm was eradicated by 2.0 log CFU/cm 2 , with further improvement to 4 log CFU/cm 2 within 2 min 30 s (50 J/cm 2 ), indicating significant photosensitivity and photodynamic efficiency of berberine. In the salmon model, the curcumin-mediated HI-BL resulted in Lm reduction rates of 0.7 log CFU/g after 50 J/cm 2 and 2.0 logs after 100 J/cm 2 . Further photoreduction was observed against the inherent microbiota, resulting in 3.4 and 3.8 log CFU/g to respective doses. Although the effective decontamination, the salmon lightness (L*) increased in a HI-BL dose-dependent manner, becoming visually perceptible after 100 J/cm 2 . Quercetin and capsaicin were less effective in both biofilm and food models. However, quercetin demonstrated promising antimicrobial activity, achieving a 4.5 log CFU/mL reduction after 3 min and 45 s (100 J/cm 2 ). At sub-inhibitory concentrations, the quercetin-mediated HI-BL down-regulated the expression of the motility genes ( fliP , flgE ) and the regulatory gene deg U, which would decrease the Lm ability of adhesion. In contrast, berberine increased the expression of motility genes ( fliP , flgE , motA ) the most, while curcumin predominantly up-regulated the virulence and stress response gene prfA . This study contributes to a better understanding of the interactions between L. monocytogenes and photosensitizers, and may help advance blue light technology against this pathogen through suitable photosensitizer selection and antimicrobial treatment optimization.

Source: Food Research International

DOI: 10.1016/j.foodres.2026.118441

Authors: Joanna Gajewska, Izabela Lipska, Aleksandra Zimińska, Arkadiusz Zakrzewski, Anna Draszanowska, Magdalena A. Olszewska

Institution: University of Warmia and Mazury in Olsztyn

Language: English

Topic: Photodynamic Therapy Research Studies

Subfield: Pulmonary and Respiratory Medicine

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $4,320