Safety Evaluation and Antibacterial Activity of Enterococci Isolated from Lighvan Cheese

Abstract

AbstractTwenty three enterococci were isolated from Lighvan cheese. Enterococcal isolates identified by 16S rDNA sequencing, were evaluated for their safety and also examined for antibacterial activity and presence of the genes coding for enterocins. Four enterococcal isolates exhibited inhibitory activity against Listeria innocua and E. faecalis and harbored the bacteriocin genes (enterocins A, B, P, X and 31) too. Multiple combinations of virulence determinant genes (vanA, vanB, gelE, esp, asa1, cpd and ace) were detected in enterococcal isolates with the exception of 5 E. faecium isolates. While the isolates exhibited resistance to some antibiotics, all of them were susceptible to ampicillin and vancomycin. In conclusion, this study shows the presence of enterococci with potential biopreservative activity in Lighvan cheese; however it also warrants further research on the safety and origins of enterococci in this cheese.Practical ApplicationsLighvan is a very popular cheese in Iran with a specific texture and taste which is produced in little amount from raw sheep milk and ripened in manmade underground galleries. There are a few studies about the microflora of this cheese and the point is that enterococcus species have proven to be always dominant. Safety evaluation of these bacteria is really necessary as far as the Lighvan cheese is produced from raw milk and also the controversial viewpoint that there is about the GRAS state of enterococcus species. Recognition of the safe strains of enterococcus species isolated from the lighvan cheese would help to produce a more hygienic and safer industrial product.