## 4 Discussion  
With the growing public demand for safe, natural, and healthy food, the development of various natural antimicrobials for effective food preservatives has attracted more attention. Enterocin Gr17 (ENT) is a bacteriocin that was previously discovered in our laboratory. It has a strong inhibitory activity against a variety of pathogenic bacteria and spoilage bacteria, excellent pH resistance, and heat stability that has the potential to be used as a food preservative [6]. Currently, studies have observed a synergistic inhibitory effect when bacterios are combined with EOs to achieve maximum lethality against food-pathogenic and spoilage bacteria. Similar results were also found in the combination of entercion and EOs, and the greatest combination was ENT and cinnamaldehyde essential oil (CEO). In addition, the antimicrobial efficacy assay in this study was carried out on food pathogens (_S. aureus, B. cereus, L. monocytogenes, S. enterica_ and _E. coli_), spoilage bacteria (_P. aeruginosa, P. fluorescens_, and _S. putrefaciens_), and pathogenic fungi (_C. albicans, A. flavus, P. expansum_, and _A. alternata_). Thus far, there have been few studies concerned with the antimicrobial effect on molds and yeast despite the fact that pathogenic fungi can produce more serious and deadly toxins during food storage [38]. The encapsulation of the antimicrobial agents into proper nanoemulsion systems provided a solution to improve the aqueous solubility and physical stability of the EOs and the chemical and thermal stability of the bacterios, which may lead to an enhanced antimicrobial effect [14]. However, the difference in the aqueous solubility of bacterios (high) and EOs (low) led to a less stable NE system; therefore, the type of emulsifier must be carefully formulated [20]. After the evaluation of droplet size, zeta potential, PDI, TSL, and EE, the NE stabilized with SPI exhibited the best stability, uniformity, and embedding efficiency. Additionally, the NE delivery systems that loaded with ENT/single or mixed were all highly stable. Similarly, the NE containing polylysine and nisin showed the smallest particles and highest stability at a concentration of 1.5% (_w_/_v_) SPI [18]. In addition, a higher DPPH radical-scavenging activity and stronger antimicrobial activities against all of the indicator microorganisms were observed in the CO-NE compared with ENT-NE and CEO-NE, indicating that CO-NE exhibited excellent antimicrobial and antioxidant effects. This was due to the synergy between ENT and CEO and the tiny droplet size of the CO-NE, which made it easier to penetrate the bacteria. Similar results were also found in the co-contained citrulus lanatus seed/phyllanthus niruri methanolic extract and curcumin/resveratrol NE system [39; 40]. Then, NE loaded with ENT and CEO was used to delay the spoilage of the liquid-smoked salmon filled during storage. Salmon is extremely perishable and would enter lipid oxidation owing to its content of unsaturated fatty acids and prooxidant molecules [1]. The spoilage of salmon is the result of three basic factors: enzymatic autolysis, oxidation, and microbial growth [38]. In our study, liquid-smoked salmon was vacuum-packed and stored at 4 \({}^{\circ}\)C to maintain low native enzyme activity. CEO, as a kind of antioxidant, was used to control lipid oxidation, resulting in the development of rancidity and a loss in quality. ENT was added to the smoked salmon to inhibit the microbial growth that was the main reason for the deterioration in salmon quality. Many of the initial microorganisms in salmon do not contribute to spoilage; only specific spoilage organisms (SSOs) were responsible for spoilage. _Pseudomonas_ spp. and _Shevanella_ spp. were the SSOs for Atlantic salmon (Salmo salar) during low-temperature storage [41]. Accordingly, SSOs participate in spoilage by degrading the nitrogenous compounds in the fish and producing unpleasant and unacceptable off-flavors, causing discoloration or slime [42].