Rapid screening system for novel LAB bacteriocins. Bacteriocins from various LAB strains are evaluated for novelty at the early stage of screening. The process of bacteriocin purification and structural analysis are tedious and time-consuming, and in most cases would lead to the isolation of known bacteriocins. Hence, it is necessary to evaluate the novelty as early as possible during the screening process. In this system ESI-LC/MS analyses of the culture supernatant, combined with principal component analysis (PCA) of their activity spectra, are employed. Potential novel bacteriocins are then selected for purification and further analyses.