Plant Extracts and Essential Oils at Concentrations Acceptable to a Sensory Panel Inactivate Salmonella Typhimurium DT104 in Ground Pork

A potential method to inhibit pathogenic bacterial growth in meat is through the introduction of plant-derived antimicrobials. Because these antimicrobials may also adversely affect the sensory characteristics of the meat, the objectives of this study were 1) to define the appropriate concentrations of olive extract, apple extract, oregano oil, and cinnamon oil added to ground pork that are acceptable to a sensory panel, and 2) to determine their antimicrobial activities against Salmonella Typhimurium DT104 in inoculated ground pork. Plant extracts were evaluated against two initial inoculum levels (6 and 4 log CFU/g of pork) of Salmonella. Sensory tests showed that acceptable concentrations of oregano and cinnamon oils were 0.5% and of olive and apple extracts were 3%, respectively. Ground pork samples were inoculated with Salmonella, treated with antimicrobials at various concentrations (0.1% - 0.5% cinnamon and oregano essential oils and 3% - 5% olive and apple extracts), and stored at 4°C for 7 days. Survivors were enumerated at days 0, 3, 5, and 7. Cinnamon oil at 0.5% and olive extract at 3% induced a 1.0 and a 0.9 log CFU/g (from 6-log CFU/g initial inoculum) reduction, respectively, at day 7. At 3%, olive extract showed a 1.06 log CFU/g maximum reduction of Salmonella from a 4-log CFU/g initial inoculum. Pork samples containing oregano oil and apple extract did not show a significant reduction compared to the control without the antimicrobials. The results indicate that cinnamon oil and olive extract can potentially be applied at consumer-acceptable concentrations against low levels of S. Typhimurium DT104 in ground pork.