## 4 Biocontrol Methods
### Postbiotics
Its unique chemical structure gives it thermal stability and resistance to proteolytic digestion, making it effective in maintaining the integrity of the bacterial cell membrane. In addition, nisin combined with other methods, such as physical treatments (e.g., electric field) or chemical agents (e.g., organic acids), has been shown to broaden its antimicrobial spectrum and reduce the amount of nisin required in food. Studies have reported that nisin can be enhanced in its antibacterial efficacy by combining it with other bacteriocins, inorganic agents, or multiple methods, such as high-intensity ultrasound or UV-A light. For example, combining nisin with these technologies provided enhanced antibacterial protection without significantly affecting product quality. However, in some cases, these combinations altered the sensory characteristics of dairy products, such as color and taste, or even texture, as was the case with some cheeses treated with encapsulated nisin over the long term. The efficacy and safety of encapsulated nisin need to be further evaluated, particularly with modern antibacterial packaging methods, which could include antibacterial agents integrated into polymers. Although nisin has demonstrated antibacterial activity against _L. monocytogenes_, its use is limited due to the high cost of isolation and purification, narrow spectrum of activity, and the risk of developing nisin resistance. Another obstacle is the potential toxicity associated with high concentrations of nisin. Nisin efficacy also varies with pH, temperature, food composition, and microbiota composition of the food product, and future research should focus on optimizing these variables. Experts recommend exploring other strategies for applying nisin, such as using nisin-producing strains in fermented foods or adding encapsulated nisin in various forms to control its gradual release and protect it from proteolytic degradation. Combining it with other antibacterial techniques may enhance efficacy while limiting adverse effects on the organoleptic characteristics of dairy products and preventing the development of nisin resistance (CDC, 2021) [9]. In addition, combinations of nisin with other natural substances, such as sesamol or carvacrol, have shown synergistic effects, increasing its antimicrobial efficacy. Recent studies have evaluated the efficacy of nisin in combination with lauric alginate and \(\varepsilon\)-polysine in cheeses. [PERSON] et al. (2020) [118] demonstrated that these combinations can effectively control _L. monocytogenes_ in fresh cheese for periods of up to 28 days of cold storage. The use of pubic acid in combination with nisin has also been investigated to increase its efficacy against Gram-negative bacteria, such as _Escherichia coli_[119]. Bactericons can be used in the food industry either by adding the producing strains to food or by extracting them in purified or semi-purified form. Studies indicate the effectiveness of bacteriocins, including nisin and pedicion, in inhibiting _L. monocytogenes_ in meat, fish, dairy products, salads, and juices [120]. For example, the application of bacteriocins on packaging prevented the growth of _L. monocytogenes_ for up to 12 weeks at 4 \({}^{\circ}\)C [22]. These liposomes reduced the number of _L. monocytogenes_ from 4.5 log cfu/mL to an undetectable level in whole milk and skim milk after 14 days of refrigerated storage at 7 \({}^{\circ}\)C. The antimicrobial peptide P34 was also encapsulated in liposomes, which was able to control _L. monocytogenes_ only in skim milk for up to 8 days. The antimicrobial activity of liposome-encapsulated nisin was also effective against _L. monocytogenes_ in fluid milk by prolonging the lag phase at both 5 \({}^{\circ}\)C and 20 \({}^{\circ}\)C. In another study, liposomesand 1,2-dioleoyloxy-3-trimethylammonium-propane were used to encapsulate sakacin, controlling the growth of _L. monocytogenes_ in goat milk for 5 days at 7 \({}^{\circ}\)C, with a reduction of approximately 5 logs compared to the control sample.