title: Photodynamic treatment: a novel method for sanitation of food handling and food processing surfaces.
abstract: The photodynamic bactericidal effect of the photoactive dyes acriflavine neutral, rose bengal, phloxine B, and malachite green (oxalate salt) at concentrations of 5 to 5,000 microg/ml against two gram-negative strains (Escherichia coli LJH 128 and Salmonella Typhimurium C1058), two gram-positive strains (Bacillus sp. C578 and Listeria monocytogenes LJH 375), and yeast (Saccharomyces cerevisiae C1172) was investigated. Incubation of the investigated bacteria with acriflavine neutral under illumination resulted in a significant reduction in cell numbers compared with dark incubation. Rose bengal caused a significant killing effect for bacteria incubated both in the dark and under illumination. Malachite green was active against gram-positive bacteria under illumination and did not affect gram-negative bacteria or yeasts. Incubation with phloxine B resulted in a significant decline in cell numbers for gram-positive bacteria, both in the dark and under illumination; gram-negative bacteria and yeasts were unaffected. Conjugation of rose bengal and phloxine B with poly(vinyl amine) resulted in an enhanced bactericidal effect during both dark and light incubation. This was explained by electrostatic interaction of the polymer with the cell surface, which resulted in closer contact of the photoactive dye and cell. No killing effect was observed for yeasts incubated with dye conjugates. Filter paper treated with dye-poly(vinyl amine) conjugates showed high photodynamic bactericidal activity against the bacterial strains, but not against the yeasts. The extent of bacterial killing depended on the nature and concentration of the dye conjugate and the type of microorganism. The presented data suggest that a photodynamic approach for constructing "self-decontaminating" materials has potential.
authors.affiliation: Canadian Research Institute for Food Safety, University of Guelph, Guelph, Ontario, Canada N1G 2W1. lbrovko@uoguelph.ca
authors.forename: Lubov Y
authors.initials: LY
authors.lastname: Brovko
authors.forename: Ann
authors.initials: A
authors.lastname: Meyer
authors.forename: Arvinder S
authors.initials: AS
authors.lastname: Tiwana
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Han
authors.initials: H
authors.lastname: Liu
authors.forename: Carlos D M
authors.initials: CD
authors.lastname: Filipe
authors.forename: Mansel W
authors.initials: MW
authors.lastname: Griffiths
mesh_terms: D001407:Bacillus / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D015169:Colony Count, Microbial; D004396:Coloring Agents / Q000494:pharmacology*; D003257:Consumer Product Safety; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004357:Drug Synergism; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D005511:Food Handling / Q000379:methods*; D005525:Food-Processing Industry / Q000379:methods*; D005517:Foodborne Diseases / Q000517:prevention & control; D006801:Humans; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D012486:Salmonella typhimurium / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects
chemical_list: D004396:Coloring Agents; D004338:Drug Combinations; D017319:Photosensitizing Agents