Evaluation of the photocatalytic antimicrobial effects of a TiO2 nanocomposite food packaging film by in vitro and in vivo tests

The ability to inactivate Pseudomonas spp. and Rhodotorula mucilaginosa by a photocatalyst thin film, obtained via a combination of anatase and rutile titanium dioxide incorporation into a low density polyethylene (LDPE) polymeric matrix by a melt blending method, was addressed in this study. The number of surviving cell of the Pseudomonas spp. was decreased by 4 log CFU/ml and 1.35 log CFU/ml after 3 h of UVA illumination on TiO2 nanocomposite thin film and LDPE thin film, respectively. The number of cells of R. mucilaginosa decreased by 2 log CFU/ml and 0.64 log CFU/ml on TiO2 nanocomposite thin film and LDPE thin film, respectively. In an in vivo test carried out on fresh pears packaged in TiO2 nanocomposite film and stored under illumination by a fluorescent light lamp at 5 C for 17 days, the number of mesophilic bacteria and yeast cells decreased significantly compared to samples stored in LDPE film. The greatest effects were recorded by combining UVA illumination and active film. It was also proven that the photocatalyst thin film prepared by extrusion could be effectively used in fruit packaging applications. (C) 2012 Elsevier Ltd. All rights reserved.