Fresh cheese biopreservation using bacteriocins producing lactic acid bacteria

Abstract

Introduction The search and research of bacteriocin(s) producing lactic acid bacteria (LAB) has become popular at the end of 2000. The usage of bacteriocin(s) (in pure form or using bacteriocin(s) producing LAB) as natural antimicrobial compounds are promising technology in food industry, medicine and marine environmental research. The application of bacteriocin(s) producing LAB may be quite wide: from biopreservation of milk, meat, poultry, vegetable and fruit products to incorporation it in the product packaging. The aim of the present study was to evaluate a few bacteriocin producing LAB as fresh cheese biopreservation agents. Methods Fresh cheese was produced using three Lactococcus lactis strains producing bacteriocin, isolated from raw goat milk, and reference L. lactis (ATCC11454) bacteria producing nisin. Before making cheese raw milk was tested for total bacteria, coliform bacteria, E. coli, Listeria monocytogenes, Salmonella and staphylococci. Microbiological evaluation of produced cheese was performed after 0h, 24h, 48h, 72h and 4 days. The changes of volatile compounds in fresh cheese were evaluated immediately after production and after 4 days using solid phase microextraction (SPME) coupled with GC-MS. Results There were not detected pathogenic bacteria, while other bacteria did not exceed standard requirements in raw milk. Salmonella, E. coli, Listeria and coliform bacteria were not detected during the storage of fresh cheese. Amount of LAB remain constant during the whole storage period. Both qualitative and quantitative changes of volatile compounds were observed by SPME-GC-MS. Conclusions Bacteriocin producing L. lactis bacteria may be used for fresh cheese biopreservation.