A bacteriocin from Carnobacterium piscicola for the control of Listeria monocytogenes in vacuum-packaged meat

Abstract

The purpose of this study was to determine the inhibitory capacity of a bacteriocin-like substance produced by Carnobacterium piscicola L103 against Listeria monocytogenes , when inoculated into vacuum-packaged meat. The bacteriocin was partially purified by ammonium sulfate precipitation and gel filtration on Sephadex G-25, followed by lyophilization. Beef steaks were inoculated with the bacteriocin and a sensitive strain of L. monocytogenes . The vacuum-packaged meat was stored at 4°C and microbial analyses were carried out every 7 days, over 21 days. Results showed that in the control steaks, without bacteriocin, counts of L. monocytogenes stayed at the initial inoculation level during the complete storage period. The naturally growing lactic acid bacteria (LAB) reached log 7·4 cfu cm−2after 14 days of storage and no inhibitory effect on the growth of the LAB was observed in the presence of the bacteriocin. The pH of the meat dropped from 5·7 to 5·0 in the inoculated as well as in the control samples, while colour and odour remained acceptable up to 14 days of storage. On the meat inoculated with bacteriocin, L. monocytogenes was completely inhibited after 14 days of storage at 4°C. It was concluded that the use of the inhibitory substance from C. piscicola L103 could be an important contribution to meat safety, when inoculated into vacuum-packaged meat.