ε -Polylysine (ε-poly-L-lysine) is produced by the fermentation of Streptomyces albulus. It has high antibacterial activity when its molecular weight is between 3600-4300, but loses activity when its molecular weight is less than 1300. Pale yellow powder, hygroscopic, almost odorless is an ideal natural antimicrobial to prolong the shelf life, with a high natural antimicrobial activity against a wide range of fungi, Gram-positive and Gram-negative bacteria, and their spores.