One hundred and fifty lactic acid bacteria (LAB) isolated from vacuum-packaged processed meats werc screened for antagonistic activity against various food spoilage microorganisms and foodborne pathogens. Nineteen strains produced bacteriocins active against closely related LAB and Lisreriu strains. Leirconostoc curno.~~im (LA54a and TA26 b) and Lriiconostoc nlrsenteroitkes subspecies rk..rrruriicwii (TA33a) produced bacteriocins that were susceptible to proteolytic enzymes, but not to catalase, lysozyme o r chloroform. They were heat stable up to 100 "C for thirty minutes at pH 2 to 7, and excl-ted a bacteriolytic effect. Bacteriocin production by all Leiiconasroc strains was growth associated, occurring at incubation temperatures of 0 "C to 30 "C and initial medium pH 4.5 to 7.5.
Probing of plasmid D N A from the three Leuconostoc strains with an oligonucleotide probe homologous to the nucleotide sequence of leucocin A-UAL 187 indicated plasmid-mediated bacteriocin production. Homology of the three Leiiconasroc bacteriocin-coding genes to the amino-terminal end of the leucocin A-UAL 187 gene from Leuconostoc gelidirm UAL 187 is therefore suggested. This evidence implies that all three Leucoiiostoc strains produce type 2. Listeriu active bacteriocins.