Control of Salmonella in chicken meat using a combination of a commercial bacteriophage and plant-based essential oils

The objectives of this study were to evaluate the antimicrobial activity of 10 essential oil compounds and to determine the combined effects with a commercial bacteriophage (SALMONELEX) against Salmonella. Thymol and carvacrol were the most active compounds tested, with a minimum inhibitory concentration (MIC) of 0.25-1 mg/ml and a minimum bactericidal concentration (MBC) of 0.5-1 mg/ml against three Salmonella strains. Multiplicity of infection (MOI), or bacteriophage/pathogen ratio (PFU/CFU), significantly affected bacteriophage efficacy in media and in chicken products. The bacteriophage decreased Salmonella Typhimurium JWC-3001 by 5 log CFU/ml at low MOI (≥1.7) in tryptic soy broth, but a higher bacteriophage concentration was needed to exhibit bactericidal effect in chicken products. Dipping of inoculated chicken in 1.6 % (w/v) thymol and carvacrol emulsions for 3 min inactivated 1.3 and 1.6 log CFU/g, respectively, of a cocktail of three Salmonella strains. A sequential dipping treatment of inoculated chicken in bacteriophage (1.1×108 PFU/ml) for 3 min and in 1.6% (w/v) thymol or carvacrol for 3 min resulted in reductions of 1.9-2.0 log CFU/g of the cocktail. The combined treatments resulted in significantly greater reduction of Salmonella than individual bacteriophage or essential oil treatments.
Source: Food Control - Category: Food Science Source Type: research