Milica Glisic

Inhibition of Salmonella by thyme essential oil and its effect on microbiological and sensory properties of minced pork meat packaged under vacuum and modified atmosphere

The antibacterial activity of thyme essential oil (TEO) was evaluated against four serovars of Salmonella (S. Enteritidis, S. Typhimurium, S. Montevideo and S. Infantis), experimentally inoculated (106CFU/g) in minced pork, which was treated with different concentrations of the TEO (0.3%, 0.6% and 0.9%) packaged under vacuum or MAP (30%O2/50%CO2/20% N2) and stored at 3±1°C for 15days. GC-MS analysis of the TEO was performed in order to determine composition, and the predominant constituent was thymol (50.48%), followed by p-cymene and linalool. The minimum inhibitory concentration was determined for each Salmonella serovar studied. Among the tested active compounds, thymol and carvacrol exhibited the greatest inhibitory effect followed by TEO, with minimum inhibitory concentrations of 320 to 640μg/ml. S. Enteritidis was the most sensitive serovar. During the storage period, Salmonella counts in pork were reduced by 1.69-4.05logCFU/g. The influence of TEO on Enterobacteriaceae, lactic acid bacteria and total viable count was determined in control mince with no added Salmonella. The most pronounced antibacterial effect was achieved by the combination MAP and 0.9% TEO. Although the antibacterial activities of all studied concentrations of TEO in pork were evident and significant (P<0.05), sensory analysis showed that 0.3% TEO was the most acceptable to trained panellists.

Content of Polycyclic Aromatic Hydrocarbons in Smoked Common Carp (Cyprinus Carpio) in Direct Conditions Using Different Filters vs Indirect Conditions

Abstract In this study, the common carp fish were smoked in direct and indirect smoke chambers. Direct smokings in craft chamber were conducted in four ways: smoked without filter (Fo), with zeolite filter (Fz), filter with granular activated carbon (Fc) and gravel filter (Fg). The content of 16 different PAHs in smoked common carp was analyzed using GCMS method. Addition of zeolite, activated carbon and gravel filters significantly reduced PAH levels (P < 0.05). Levels of naphthalene, acenaphthylene, fluorine, phenanthrene and fluoranthene were reduced using zeolite, activated carbon and gravel filters by 42.14, 40.64, 42.5 (Naph), 49.81, 48.96, 48.96 (Acy), 32.71, 30.79, 26.15 (Fln), 28.79, 31.68, 18.34 (Phe) and 4.14, 3.87 and 1.12 (Flt) µg/kg, respectively. The addition of zeolite and activated carbon filters reduced amount of anthracene by 15.28 and 11.89 µg/kg and amount of pyrene by 1.25 and 0.6 µg/kg, while addition of gravel filters did not influence significantly these PAHs (P > 0.05). However all filters decreased acenaphthene, benz[a]anthracene and chrysene below detection limits. Zeolite was the most effective adsorbent for PAHs. All samples were under maximum limit of BaP (2 μg/kg) and PAH4 (12 μg/kg) set by European Commission Regulation 835/2011. Based on results in the present study it can be stated that common carp smoked in both direct and indirect conditions can be considered to be safe for consumption.