Detection of bacteriocin-producing lactic acid bacteria from milk in various farms in north-east Algeria by a new procedure

Twelve samples of bacteriocin-producing lactic acid bacteria were isolated from raw milk. The screening procedure has the advantage of differentiating directly on agar plates active colonies among thenatural microbial population without subsequent culture. Five of milk isolates had effective inhibitory activity against Staphylococcus, Bacillus and all Listeria monocytogenes strains tested. In addition, two bacteriocinogenic isolates were effective against Gram-negative bacteria including Pseudomonas aeruginosa and Escherichia coli. The action of the bacteriocins was eliminated by a proteolytic enzyme. Simulation tests in liquid medium showed a 3 log reduction of Listeria growth in presence of bacteriocin during a period stockage of 14 days at 4°C.