Control of Listeria monocytogenes contamination in fresh beef by using lactococcin BZ

The aim of this study was to investigate the inhibitory effect of lactococcin BZ produced by Lactococcus lactis spp. lactis BZ against Listeria monocytogenes in raw beef. Lactococcin BZ depending on concentration (400–3,200 AU/ml) reduced the counts of L. monocytogenes attached to meat surface (from 4.71 log CFU/g to undetectable level, and from 7.92 to 3.64 log CFU/g) in 5 min. When meat samples were simultaneously inoculated with lactococcin BZ and L. monocytogenes, lactococcin BZ reduced the count of non‐attached Listeria cells in 5 min by 1.58–5.03 (undetectable level) log cycles in the low inoculum (5.03 log CFU/g) and 1.11–5.58 log cycles in the large inoculum (7.86 log CFU/g) compared to control samples. Also, lactococcin BZ at 400–3,200 AU/ml reduced the number of L. monocytogenes in meat samples inoculated at 2.45, 4.42, and 7.29 log CFU/g throughout 12 day storage at 4 °C and maintained its biological activity. In addition, lactococcin BZ adsorbed to meat surface and adsorption did not adversely affected antilisterial activity. Practical applications In this study, we investigated the inhibitory effect of lactococcin BZ produced by Lactococcus lactis spp. lactis BZ against Listeria monocytogenes during, after or before attachment on raw beef. It was observed that lactococcin BZ depending on its concentration (400–3,200 AU/ml) and amount level of Listeria cells (4.71 or 7.92 log CFU/g) reduced the cell counts of L. monocytogenes in the meat samples very effectively. Lactococcin BZ at 1,600 and 3,200 AU/ml showed strong antilisterial activity toward L. monocytogenes before, during and after attachment to meat samples, but its antilisterial activity was higher before or during attachment than after attachment. Therefore, lactococcin BZ could be potential alternatives to chemical preservatives for meat industry.