Influence of oregano essential oil on the inhibition of selected pathogens in “Alheira” during storage

Abstract

Background. Plant-derived essential oils (EOs) have shown remarkable antimicrobial potential against spoilage and pathogenic microorganisms in meat and meat products. The aim of this study was to investigate the influence of oregano EO on the inhibition of Salmonella Enteritidis, Listeria monocytogenes and Staphylococcus aureus in an internal mixture of "Alheira" during storage. Material and methods. Different concentrations of oregano EO (4%, 1.5%, 0.5%, 0.195% and 0.0975%) were evaluated against the selected pathogens during 21 days of storage at 4°C. The pH and water activity values and lactic acid bacteria (LAB) counts were also evaluated. Finally, sensory assessment was performed. Results. The antibacterial effect varied according to the oregano EO concentration used, and target pathogen. Oregano EO at 4% demonstrated the highest antimicrobial activity against all the pathogens tested. The lowest concentrations used (0.195% and 0.0975%) resulted in ~2-3 log reduction, but only for L. monocytogenes after 21 days of storage. Counts of LAB were ~10 9 CFU/ml for all samples and no differences in the pH and a w values were detected between samples. However, at a concentration of 0.195%, Oregano EO had a negative impact on consumer acceptance of "Alheira". Conclusion. These results could be interesting for the meat industry, as a starting point for other studies that have now to concentrate on strategies to "mask" unpleasant sensorial alterations caused by EOs in "Alheira" and helping the industry to ensure the microbiological safety of its products.

Biocontrol of Pathogen Microorganisms in Ripened Foods of Animal Origin

“…Additionally, several strains belonging to species that are part of the LAB group have acquired QPS (Qualified Presumption of Safety) status [ 75 ]. Members of the genera Lactobacilli and members of the genera Lactococcus and Pediococcus were the most commonly explored, namely Latilactobacillus curvatus , L. sakei , Lactiplantibacillus plantarum , Limosilactobacillus fermentum , Lactococcus lactis and Pediococcus acidilactici [ 71 , 76 , 77 , 78 ]. Furthermore, LAB have frequently been used as starters or protective cultures due to their natural ability to dominate the microbial population of many foods.…”

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“…Terpenes are a single class of aromatic compounds found in essential oils 119 . The antimicrobial activity of terpenes depends on hydrophobic activity, cytoplasmic membrane disturbance, electron flow disturbance, active transport, and cell material coagulation 120 .…”

Natural Plant-Derived Chemical Compounds as Listeria monocytogenes Inhibitors In Vitro and in Food Model Systems

“…Many of them come from spices known for centuries and widely used for seasoning food products. EOs have also been successfully used for reduction of L. monocytogenes not only in vitro, but also in various food model systems (including meat, milk, vegetables and fruits) as published by many authors even in recent years [17,[24][25][26][27][28][29][30][31][32][33][34][35]. Not only EOs are antilisterial, but also various extracts, for example grape extracts (skin, seed, stems, pomace, juice and berries extracts) [36][37][38], blueberries extracts [37], lowbush berries extracts [39], apple skin, olive pomace, olive juice powder extracts [40] and grapefruit seed extract [41], as well as Achillea schurii flowers extracts [42] showed activity against L. monocytogenes.…”