Two Different Processes to Obtain Antimicrobial Packaging Containing Natural Oils

In this study, antimicrobial packaging materials were developed by incorporating known concentrations (w/w) of essentials oils of oregano (Origanum vulgare) and thyme (Thymus vulgaris) into low-density polyethylene (LDPE), suitable for use as food packaging, via two different methods: ionizing treatment and directly by extrusion. The mechanical, barrier, and antimicrobial properties of the packaging were evaluated against the following foodborne pathogens: Salmonella typhimurium, Listeria monocytogenes, and Escherichia coli O157:H7. The results demonstrate that films developed by extrusion incorporating 4% (w/w) of essential oils had a higher inhibitory effect than those obtained using the ionizing treatment. The packaging developed by extrusion containing 1% (w/w) showed a positive inhibitory effect, while those obtained by the ionizing treatment had no inhibitory effect against any of the test microorganisms. The incorporation of essential oils on the LDPE films generated a plasticizer effect, whereas the ones obtained by means of ionizing treatment did significantly affect the barrier properties of the films. The results of this study showed that plant-derived essential oils could be incorporated in active films for food packaging.