Inactivation of Bacillus cereus by Na-chlorophyllin-based photosensitization on the surface of packaging.

Abstract

AIMS:

This study was focused on the possibility to inactivate food-borne pathogen Bacillus cereus by Na-chlorophyllin (Na-Chl)-based photosensitization in vitro and after attachment to the surface of packaging material.

METHODS AND RESULTS:

Bacillus cereus in vitro or attached to the packaging was incubated with Na-Chl (7·5×10(-8) to 7·5×10(-5) mol l(-1) ) for 2-60min in phosphate buffer saline. Photosensitization was performed by illuminating cells under a light with a λ of 400nm and an energy density of 20mW cm(-2) . The illumination time varied 0-5min and subsequently the total energy dose was 0-6J cm(-2) . The results show that B. cereus vegetative cells in vitro or attached to the surface of packaging after incubation with 7·5×10(-7) mol l(-1) Na-Chl and following illumination were inactivated by 7log. The photoinactivation of B. cereus spores in vitro by 4log required higher (7·5×10(-6) mol l(-1) ) Na-Chl concentration. Decontamination of packaging material from attached spores by photosensitization reached 5log at 7·5×10(-5) mol l(-1) Na-Chl concentration. Comparative analysis of different packaging decontamination treatments indicates that washing with water can diminish pathogen population on the surface by <1log, 100ppm Na-hypochlorite reduces the pathogens about 1·7log and 200ppm Na-hypochlorite by 2·2log. Meanwhile, Na-Chl-based photosensitization reduces bacteria on the surface by 4·2 orders of magnitude.

CONCLUSIONS:

Food-borne pathogen B. cereus could be effectively inactivated (7log) by Na-Chl-based photosensitization in vitro and on the surface of packaging material. Spores are more resistant than vegetative cells to photosensitization-based inactivation. Comparison of different surface decontamination treatments indicates that Na-Chl-based photosensitization is much more effective antibacterial tool than washing with water or 200ppm Na-hypochlorite.

SIGNIFICANCE AND IMPACT OF THE STUDY:

Our data support the idea that Na-Chl-based photosensitization has great potential for future application as an environment-friendly, nonthermal surface decontamination technique.

• Authors: Z Luksiene, I Buchovec, E Paskeviciute
• Journal: Journal of applied microbiology (J Appl Microbiol) Vol. 109 Issue 5 Pg. 1540-8 (Nov 2010) ISSN: 1365-2672 [Electronic] England
• PMID: 20557405 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.

Chemical References

• Anti-Infective Agents
• Chlorophyllides
• chlorophyllin

Topics

• Anti-Infective Agents (pharmacology)
• Bacillus cereus (drug effects, radiation effects)
• Chlorophyllides (pharmacology)
• Decontamination (methods)
• Food Handling (methods)
• Light
• Microbial Viability
• Product Packaging