Active food packaging films with synergistic antimicrobial activity

•LDPE films containing encapsulated synergistic mixture of essential oils - EOs for food packaging.•Loading EOs in HNTs allows production of LDPE films employing conventional processing equipment.•Films show potent and prolonged antimicrobial activity in vitro and in real food system.•Films outperform systems containing the individual essential oils by orders of magnitude.•Using synergistic EOs combination allows reducing the EOs content.

High-quality polymer nanocomposites containing a synergistic antimicrobial combination of essential oils (carvacrol and thymol mixtures) are produced and their outstanding performance as an active packaging for hummus is demonstrated. The interactive properties of carvacrol and thymol against E. coli are studied in vitro, as the combination of these essential oils (EOs), which provides a synergistic antimicrobial action, is loaded into halloysite nanotubes (HNTs) for the first time. The latter nano-scale carriers minimize the loss of the highly volatile EOs during the high-temperature polymer processing, enabling melt compounding and subsequent film production on a semi-industrial scale. The resulting films exhibit a synergistic antimicrobial activity against E. coli, outperforming films containing the individual EOs by both potency and shelf life. The films are also integrated into real food packaging, and their effect on E. coli growth in inoculated hummus is studied. Bacterial growth is reduced by seven orders of magnitude, leading to their complete eradication, while the antimicrobial performance of the control films was significantly weaker. These results demonstrate the immense potential of these films as food packaging materials to efficiently control bacteria growth in complex food systems.

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