Bacteriocinogenic and virulence potential of E nterococcus isolates obtained from raw milk and cheese

Aims To provide molecular and phenotypical characterization of E nterococcus isolates obtained from raw milk and cheese, regarding their bacteriocinogenic and virulence activity. Methods and Results Forty‐three bacteriocinogenic enterococci isolates were identified by 16s rDNA , fingerprinted by RAPD ‐ PCR analysis and tested by PCR for the presence of genes for lantibiotics ( lan M , lan B and lan C ) and enterocins ( ent A , ent B , ent P , ent L 50 AB and ent AS 48) and by phenotypical methods for bacteriocin production and inhibitory spectrum. Also, the virulence of the isolates was evaluated by PCR for genes gel E , hyl , asa 1, esp , cyl A , efa A , ace , van A , van B , hdc 1, hdc 2, tdc and odc and by phenotypical tests for gelatinase, lipase, DNA se and α‐ and β‐haemolysis. Most isolates (93·0%) harboured at least one lantibiotic or enterocin gene and were positive for several tested virulence genes, mainly asa 1 (100%), gel E (93·0%) and efa A (83·7%). 53·5% of the isolates presented β‐haemolysis. Conclusions Enterococcus spp. isolates presented an interesting potential application for food preservation because of bacteriocin production; however, virulence‐related genes were identified in all RAPD profiles. Significance and Impact of the Study The study demonstrated the contradictory characteristics of the tested E nterococcus isolates: they presented a good potential for application in food biopreservation but contained several virulence factors.