ANTIBACTERIAL ACTIVITY OF CARVACROL, CITRAL, AND GERANIOL AGAINST SALMONELLA-TYPHIMURIUM IN CULTURE-MEDIUM AND ON FISH CUBES

Carvacrol, citral and geraniol showed potent antibacterial activity ag ainst Salmonella typhimurium and its rifampicin-resistant (Rif(R)) str ain as determined in tryptic soy broth and by zone of inhibition on ag ar-based medium. Carvacrol had the most potent bactericidal activity, with minimum inhibitory and bactericidal concentrations (MIC and MBC) of 250 mu g/mL for both tester strains. When tested at 0.5, 1.5 and 3. 0% in 1% Tween 20 for bactericidal activity against Rif(R)-S. typhimur ium inoculated on fish cubes, carvacrol at 3.0% completely killed the inoculated bacteria, while geraniol killed most of the bacteria, and c itral killed the least. Carvacrol and geraniol showed potent antibacte rial activity at 1.5%. Bactericidal activity became more evident as st orage of fish cubes at 4 degrees C lengthened. The comparable inhibiti on of these strains of Salmonella and species of Gram-negative bacteri a by carvacrol and geraniol support their application as potential ant ibacterial agents in food systems.