Novel Approach to Effective and Uniform Inactivation of Gram-Positive Listeria monocytogenes and Gram-Negative Salmonella enterica by Photosensitization

Zivile Luksiene1,2, Rita Kokstaite1, Pranas Katauskis2 and Vladas Skakauskas2*

1Institute of Applied Research, Vilnius University, Sauletekio 10, LT-10223 Vilnius, Lithuania
Faculty of Mathematics and Informatics, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania

Article history:

Received May 10, 2012

Accepted November 5, 2012

Key words:

photosensitization, chlorophyllin, aminolevulinic acid, Salmonella enterica, Listeria monocytogenes


The aim of this work is to compare the antimicrobial efficiency of aminolevulinic acid- -based photosensitization (ALA-photo) and chlorophyllin-based photosensitization (CHL- -photo) against Gram-positive Listeria monocytogenes and Gram-negative Salmonella enterica, to assess some quantitative inactivation parameters of their survival curves and to propose a strategy for their effective inactivation. Cells were incubated with CHL (7.5·10–5–7.5·10–8 M) or ALA (7.5 mM) and then illuminated with visible light (λ=400 nm). The analysis of bacterial survival curves indicates that Salmonella is more resistant to CHL-photo than to ALA-photo. The shoulder of the inactivation curve was longer and the population reduction suddenness was smaller than that after ALA-photo. Listeria was more sensitive to CHL-photo than to ALA-photo. No shoulder of the survival curves of Listeria was detected after CHL-photo. Examination of bacterial survival curves enabled the determination of the optimal experimental set-up for combined ALA- and CHL-photo treatments. The obtained results indicate that both Salmonella and Listeria were inactivated to an undetectable level when combined treatment was applied. Thus, combined ALA- and CHL- -photo treatment may be an effective tool to increase effective inactivation of both Gram(+) and Gram(–) food pathogens. Experimental results and the analysis of survival curves suggest innovative approach to combat Gram(+) and Gram(–) bacteria by photosensitization in effective and uniform way.  

*Corresponding author:
                                               ++370 5 219 3084
                                               ++370 5 215 1585

Search FTB

Follow us

 facebook 1 twitter bird_icon LI In Bug


Environmental Policy

sdg publishers compact 4 300x300

QR Code


We use cookies to improve our website and your experience when using it. Cookies used for the essential operation of the site have already been set. To find out more about the cookies we use and how to delete them, see our privacy policy.

I accept cookies from this site.

EU Cookie Directive Module Information