Antimicrobial Activity of Oregano Essential Oil Incorporated in Sodium Alginate Edible Films: Control of <i>Listeria monocytogenes</i> and Spoilage in Ham Slices Treated with High Pressure Processing

• Main Authors: Foteini Pavli, Anthoula A. Argyri, Panagiotis Skandamis, George-John Nychas, Chrysoula Tassou, Nikos Chorianopoulos
• Format: Article
• Language: English
• Published: MDPI AG 2019-11-01
• Series: Materials
• Subjects: <i>listeria monocytogenes</i>; spoilage; ready-to-eat meat, antimicrobial packaging; antimicrobial compounds; non-thermal processing, infrared spectroscopy
• Online Access: https://www.mdpi.com/1996-1944/12/22/3726

The aim of the study was to evaluate the efficacy of oregano essential oil (OEO) incorporated in Na-alginate edible films when applied to sliced ham inoculated with a cocktail of <i>Listeria monocytogenes</i> strains, with or without pretreatment by high pressure processing (HPP). Microbiological, physicochemical and sensory analyses (in <i>Listeria</i>-free slices) were performed, while, the presence/absence and the relative abundance of each <i>Listeria</i> strain, was monitored by pulsed field gel electrophoresis (PFGE). The OEO incorporation in the films, caused approximately 1.5 log reduction in <i>Listeria</i> population at 8 and 12 &#176;C at the end of the storage period, and almost 2.5 log reduction at 4 &#176;C. The HPP treatment caused 1 log reduction to the initial <i>Listeria</i> population, while levels kept on decreasing throughout the storage for all the tested temperatures. The pH of the samples was higher in the cases where HPP was involved, and the samples were evaluated as less spoiled. Furthermore, the presence of OEO in the films resulted in color differences compared to the control samples, whilst the aroma of these samples was improved. In conclusion, the combined application of HPP and OEO edible films on the slices, led to a significant reduction or absence of the pathogen.