Methods for Determination of Antimicrobial Activity of Bacteriocins of Lactic Acid Bacteria

There are different methods used for the determination of antimicrobial activity of bacteriocins. The most commonly used are the disk-diffusion and dilution methods. The other methods such as point inoculation method, agar overlay assay, cross streak method, radial streak method, agar plug diffusion method, spot-on-lawn assay, Oxford cup method, agar well diffusion assay, and vesicle-based colorimetric assay are also used for the determination of antimicrobial activity of bacteriocins. The inhibitory effect of bacteriocins is dependent on time, concentration and type of bacteriocins. The antimicrobial activity is also dependent on the solid or liquid medium used for the growth of indicator bacteria. A vesicle-based assay which is indicator-independent has also been used for the detection of antimicrobial activity of bacteriocins. In this review, we have discussed the conventional and modern methods which are indicator-dependent and -independent for the detection of bacteriocins and high-throughput screening of bacteriocin-producing strains of lactic acid bacteria.