Anti-Listeria activity of lactic acid bacteria isolated from golka, a regional cheese produced in Poland Anna Sip, Micha1 Wie ˛ ckowicz * , Agnieszka Olejnik-Schmidt, W1 odzimierz Grajek Department of Biotechnology and Food Microbiology, Pozna n University of Life Sciences, Wojska Polskiego 48, 60-627 Pozna n, Poland article info Article history: Received 25 June 2011 Received in revised form 18 December 2011 Accepted 3 January 2012 Keywords: Golka Lactic acid bacteria Anti-Listeria activity Bacteriocins PCR abstract Eight hundred lactic acid bacteria (LAB) strains isolated from golka, one of the oldest and most popular regional cheese produced in Poland, were screened for anti-Listeria activity. Nearly one third of isolates showed antagonistic activity against Listeria monocytogenes. Seven strains produced other substances active against L. monocytogenes. These substances were detected in neutralized cell-free supernatant fluids and were classified as bacteriocins. 16S rDNA identification of the selected bacteriocin-producing bacteria was performed. By using primers specific to a fragment of class IIa bacteriocin-coding genes, developed by the authors, presence of the bacteriocin structural gene was confirmed for all Lactococcus garvieae strains, Leuconostoc mesenteroides 453Lab and Lactobacillus plan- tarum Lab572. Presence of the class IIa bacteriocin-coding genes within genomes of non-bacteriocin- producing strains Lactococcus lactis subsp. lactis was also detected. Bacteriocins with the highest activity against Listeria, i.e. bacteriocins of L. garvieae Lab428, Lc. mesenteroides Lab25 and Lb. plantarum Lab572 strains, were partially characterized. The bacteriocins did not adhere to surface of the producer cells and exhibit a bactericidal mode of action. Bacteriocin of L. garvieae 428Lab was produced at much higher levels (12.800 AU/ml), as compared to the other bacteriocins (3.200 AU/ml). Our results indicate that golka cheese is a rich source of LAB active against L. monocytogenes. The bacteriocinogenic isolates from golka described in this work may potentially find application as starter or protective cultures and could constitute a superb genetic pool for production of new bacteriocins. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Listeria monocytogenes is a foodborne pathogen that causes a disease known as listeriosis. L. monocytogenes primarily infects susceptible individuals such as newborns, pregnant women, elderly people, and immunocompromised adults. It is a causative agent of abortions, gastrointestinal diseases or septicaemia, and often leads to the death of infected individuals (Doganay, 2003; Orndorff, Hamrick, Smoak, & Havell, 2006). The levels of L. monocytogenes in foods that caused listeriosis in healthy adults, have varied between 10 5 and 10 9 CFU/g. For susceptible individuals even less than 100 CFU/g of the invasive form of L. monocytogenes can cause health issues (Maijala et al., 2001). Approximately 1600 cases of listeriosis have been reported each year in the United States of America only. Of these, about 260 cases of listeriosis result in death (CDC, 2009). L. monocytogenes is able to grow at the temperatures between 1.5 and þ45  C, at the salt concentrations up to 12%, at pH values near 4.5, at the a w about 0.92 and can survive in a variety of foods for long periods of time (Gandhi & Chikindas, 2007). The resistance of L. monocytogenes to several environmental factors makes this organism difficult to control in foods. A wide variety of lactic acid bacteria (LAB) strains display the capacity to inhibit growth of this pathogen. Same LAB produce inhibitory substances active against L. monocytogenes (Schillinger, Geisen, & Holzapfel, 1996). Among the anti-Listeria substances produced by LAB, bacteriocins have demonstrated a particularly strong anti-Listeria activity. Bacteriocins are ribosomally synthesized proteinaceous compounds, active directly against taxonomically related bacteria (Tagg, Dajani, & Wannamaker, 1976). Depending on their biochemical and genetic properties, these substances have been divided into four classes (Klaenhammer, 1993). Bacteriocins active against Listeria sp. belong to either class I or II. The recent investi- gations showed that class IIa bacteriocins exert the highest inhib- itory effect on L. monocytogenes. Most class IIa bacteriocins kill the targeted cells by membrane permeabilization and successive leakage of intracellular metabolites (Ennahar, Sashihara, Sonomoto, & Ishizaki, 2000). Class IIa bacteriocins demonstrate a high level of homology (between 40 and 60%) in their primary structure, in particular among the cationic N-terminal domain (Drider, Fimland, * Corresponding author. Tel.: þ48 618466022; fax: þ48 618466003. E-mail address: wieckom@up.poznan.pl (M. Wie ˛ ckowicz). Contents lists available at SciVerse ScienceDirect Food Control journal homepage: www.elsevier.com/locate/foodcont 0956-7135/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodcont.2012.01.014 Food Control 26 (2012) 117e124