ε-Poly-L-lysine is widely used as a natural preservative in the food industry due to its strong antimicrobial properties. It effectively inhibits the growth of bacteria, yeast, and molds, making it suitable for extending the shelf life of various food products such as cooked rice, noodles, sauces, and dairy items. Its safety and biodegradability have led to its approval as a food additive in many countries. Additionally, it is employed in the biomedical field for drug delivery systems, as it can form stable complexes with nucleic acids and other therapeutic agents. In cosmetics, it is utilized for its moisturizing and antimicrobial effects, enhancing the stability and safety of skincare products. Its versatility and non-toxic nature make it a valuable component across multiple industries.