ε-Polylysine hydrochloride is a natural preservative extracted from the fermentation broth of Streptomyces albulus through controlled fermentation, followed by ion exchange resin adsorption, desorption, and purification. It contains 25–35 L-lysine residues and has significant inhibitory effects against common foodborne pathogens.
ε-Polylysine hydrochloride exhibits broad-spectrum antibacterial activity, effectively inhibiting Gram-positive and Gram-negative bacteria, yeasts, molds, and other microorganisms. Specifically, it has a strong inhibitory effect on foodborne pathogens, including Aeromonas hydrophila, Pseudomonas aeruginosa, Pseudomonas fluorescens, Proteus vulgaris, Escherichia coli, Campylobacter jejuni, Salmonella typhimurium, and other bacteria associated with food poisoning and spoilage. Additionally, it also has antiviral activity; for example, at a concentration of 500 μg/ml, certain bacteriophages are significantly inactivated, with survival rates as low as 0–27%.
ε-polylysine hydrochloride not only exhibits excellent antibacterial effects on Gram-negative bacteria (such as Escherichia coli and Salmonella), which are less susceptible to other natural preservatives like Nisin, but its inhibitory effects remain stable under high temperatures, a wide range of pH values, and when used in combination with other food additives. For example, at high temperatures (such as 121°C for 30 minutes), ε-polylysine hydrochloride remains stable, without decomposition or loss of activity, making it suitable for use in heat processing of products. It also maintains strong antibacterial activity within a pH range of 2–9, compensating for the lower effectiveness of other preservatives under neutral and alkaline conditions. Moreover, when used in combination with other food additives (such as acetic acid, ethanol, glycine, organic acids, etc.), it can synergistically enhance its antibacterial effects, significantly improving its overall performance.
The safety of ε-polylysine hydrochloride is also very high. It is metabolized into lysine in the human body, and lysine is one of the essential amino acids required by humans. It is also an amino acid approved for use in food fortification by many countries worldwide. Therefore, ε-polylysine hydrochloride is a nutritive antimicrobial agent, with an acute oral toxicity LD50 of 5 g/kg, comparable to that of table salt. Radioactive isotope-labeled ε-polylysine experiments in mice have shown that 94% of the ε-polylysine is excreted, with no accumulation in tissues or organs. A small amount of ε-polylysine is degraded into lysine or short-chain polymers (4–6 units), which can be utilized by the body to synthesize proteins or enter further metabolic processes.
Due to its above-mentioned advantages, ε-polylysine hydrochloride is widely used in various food products such as cakes, pastries, fast food, butter, salad dressings, beverages, meat products, canned goods, etc. Additionally, it is used in cosmetics, personal care products, and the pharmaceutical industry to provide natural preservative protection for these products.
ε-Polylysine hydrochloride exhibits significant inhibitory effects on common foodborne pathogens, with high safety and wide applications. It is an ideal natural preservative that helps ensure food safety and extends shelf life.