Inhibitory effect of natural extract mixtures on microbial growth and lipid oxidation of sausages during storage

Large amounts of additives are used during the processing of meat products to maintain their quality and shelf life. With the growing interest in healthy eating, natural plant-based additives are being used as alternatives to synthetic additives. In this study, six types of natural extracts with excellent antibacterial activities were selected, and their antibacterial and antioxidant activities against four types of pathogens were evaluated in various combinations. In addition, the pH, color, amount of thiobarbituric acid reactive substances (TBARSs), and growth of pathogenic microorganisms during the storage of sausages treated with various combinations of the extracts were analyzed. The natural extract mixtures exhibited different antibacterial activities, depending on the combination. Compared to grapefruit seed extract, a mixture of natural extracts extracted with ethanol (M4) reduced the <italic>Escherichia coli</italic> content by more than 99.9% after 8 days of storage and slowed the growth of <italic>L. monocytogenes</italic> and <italic>Salmonella</italic> spp. by more than 80% at 14 days. Compared to untreated (NC) and grapefruit extract (PC)-treated sausages, sausages treated with the natural extract mixtures showed a significant decrease in the CIE L* and an increase in the CIE a* and CIE b* (<italic>p</italic> &lt; 0.05). The pH value was significantly lower in sausages with natural extract mixtures than in NC and PC sausages (<italic>p</italic> &lt; 0.05). The natural plant extract mixtures significantly prevented lipid oxidation (<italic>p</italic> &lt; 0.05). In sum, different types of natural extract mixtures have a synergistic effect when used together, suggesting that natural preservatives can generally inhibit the growth of microorganisms and oxidation of processed meats.