Kalb, Larissa and Eckl, Daniel and Eichner, Anja and Muranyi, Peter and Baeumler, Wolfgang (2023) Photodynamic inactivation of Salmonella enterica and Listeria monocytogenes inoculated onto stainless steel or polyurethane surfaces. FOOD MICROBIOLOGY, 110: 104174. ISSN 0740-0020, 1095-9998
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The photodynamic inactivation (PDI) uses molecules (photosensitizers) that absorb visible light (385-450 nm) energy, transfer it to adjacent molecular oxygen and thereby generating the biocidal singlet oxygen and other reactive oxygen species in situ. Efficacy of PDI was tested against Listeria monocytogenes and Salmonella enterica in three ways. Firstly, by adding the photosensitizer to bacterial suspensions. Secondly, bacteria were placed on inanimate surfaces and then sprayed with a photosensitizer suspension. Thirdly, bacteria were placed on coated inanimate surfaces, where the photosensitizer was permanently fixed in this coating (antimicrobial coating, AMC). Experiments were performed without and with soiling (albumin, sheep erythrocytes). In suspension, PDI reduced the number of viable Listeria monocytogenes and Salmonella enterica by more than 6 Log CFU/mL within seconds of light exposure. Photosensitizer spray suspension reduced the bacterial burden on surfaces with up to about 6 Log CFU/mL (5 s light exposure). PDI, even in the presence of high soiling, achieved a reduction of up to 5.1 +/- 1.2 Log CFU/mL. The AMC showed a bacterial reduction that decreased from 5.1 to 0.7 Log CFU/mL with increasing soiling. Depending on the soiling and the respective bacteria, the spray suspension or AMC achieved a bacterial reduction on the running conveyor belt demonstrator ranging from 2.9 to 5.3 or 0.5 to 4.5 Log CFU/mL, respectively. PDI used visible light, phenalene-1-one and curcumin photosensitizers, and oxygen from ambient air to reduce the bioburden on typical surfaces in food processing. The AMC acts slower than the spray suspension but enables a permanent, self-sanitizing effect.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SINGLET OXYGEN; FOOD SAFETY; LIGHT; CURCUMIN; MEAT; DECONTAMINATION; CONTAMINATION; TECHNOLOGIES; COMBINATION; RESISTANCE; Food; Pathogenic bacteria; Photodynamic inactivation; Photosensitizers; Visible light; Surfaces; Antimicrobial coating |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Dermatologie und Venerologie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 31 Jan 2024 10:59 |
| Last Modified: | 31 Jan 2024 10:59 |
| URI: | https://pred.uni-regensburg.de/id/eprint/56638 |
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