Ultraviolet-C Light Inactivation Kinetics of E. coli on Bologna Beef Packaged in Plastic Films

Abstract

This study investigated the effects of ultraviolet-C (UV-C) light as a postpackaging treatment on Escherichia coli K-12 on bologna meat packaged in polyethylene (PE), oriented polypropylene (OPP), and ClearTite® films. Findings show that PE film had the highest measured UV-C light transparency among the 15 tested films, at 76 %, followed by PP and OPP films, with 59 and 57 %, respectively. Exposure of PE film inoculated with E. coli K-12 with UV-C light resulted in a 4.6 log CFU/ml reduction after a dose of 164 mJ/cm2. Reduction of E. coli K-12 on inoculated bologna packaged in PE film was higher (1.48 log CFU/g) compared to the other films (OPP and ClearTite®) following treatment with 0.406 J/cm2 of UV-C. The surface-free energy of films was used as an indicator for changes to film surface properties. UV-C light exposure of PE, OPP, and ClearTite® films at doses in this study had no significant effect (P ≥ 0.05) on the surface properties of the treated films. This study demonstrated that treating ready-to-eat meat products, such as a bologna with UV-C light after packaging, can reduce E. coli populations by a 1.5 log cycle without negatively impacting the surface properties of plastic films.