| dc.description.abstract | Foodborne illnesses, caused by Salmonella Enteritidis, Salmonella Typhimurium, Listeria
monocytogenes and Yersinia enterocolitica, are a major public health problem worldwide. In this
doctoral dissertation, the selected foodborne pathogens isolated from meat processing, were
confirmed by MALDI-TOF MS, while the composition of 18 essential oils was determined using
gas chromatography-mass spectrometry (GC-MS). The antibacterial activity of 18 essential oils was
evaluated against 16 bacterial strains, followed by determination of minimum inhibitory (MIC) and
bactericidal (MBC) concentrations. All of the isolates formed biofilm on two common surfaces
found in the meat industry, polystyrene and stainless steel. Formation of biofilm was found to be
dependent on the availability of nutrients and the temperature. After treatment with selected
essential oils, the reduction in biofilm biomass was in the range between 30.93% and 90.28%.
Micromorphological changes on the isolates of the bacteria treated by oregano and thyme essential
oils were observed in the form of impaired cell integrity and cell lyses using SEM. Oregano and
thyme essential oils (MIC and 2MIC) significantly (p < 0.05) reduced the population of S.
Enteritidis, L. monocytogenes, and Y. enterocolitica in minced pork meat during the storage. On the
other hand, the effect of oregano and thyme essential oils was not observed against S. Typhimurium
in same conditions. Sensory evaluation of oregano and thyme essential oils on minced pork as a
food model was conducted and panelist considered that they improved sensory properties, such as
color and off-odor, during storage at 4 ± 1 °C under aerobic conditions. The obtained results
indicate that the selected essential oils can be effectively used in the meat industry as a natural
alternative to synthetic additives and disinfectants. | en_US |
