Antibacterial effect of bacteriocinogenic enterococci from different sources on listeria monocytogenes

Abstract

In this study, antimicrobial activity of partially purified enterocins and crude bacteriocins from Enterococcus isolates with different sources was investigated against Listeria monocytogenes by disk diffusion assay. Totally 70% of enterococcal isolates (Enterococcus faecalis and Enterococcus faecium from food and clinical sources) were found as potential bacteriocinogenic strains. Both of food and clinical enterococcal isolates also exhibited antimicrobial properties against L. monocytogenes. Additionally, the present study detected that inhibitory activity was strain-specific. Both crude bacteriocins and partially purified enterocins from E. faecium isolates showed lower antimicrobial activity against L. monocytogenes than E. faecalis isolates. The inhibition diameters obtained with crude enterocins and partially purified enterocins were respectively ranging from 12.33 mm to 13.25 mm and from 8.66 mm to 9.25 mm. Crude bacteriocins retained antibacterial activity after heat treatment except 120°C and also remained functional at pH values between 3 and 11. As a result, it was considered that enterocins could be benefit in heated and acidic or basic food products as biopreservative.