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The effect of different concentrations of Zataria multiflora Boiss. essential oil (EO; 0%, 0.005%, and 0.015%), nisin (0, 0.125, and 0.25 microL/mL), and their combinations on the production of staphylococcal enterotoxin C (SEC) and alpha-hemolysin (alpha-toxin) by Staphylococcus aureus at different inoculation levels (10(3), 10(4), and 10(5) cfu/mL) in brain heart infusion broth during storage at 35 degrees C for up to 43 days was evaluated. The SEC production was significantly (p < 0.05) inhibited and the hemolysis due to alpha-toxin was significantly (p < 0.05) reduced by EO concentration at levels 0.015% and 0.005%, respectively. Significant (p < 0.05) inhibitory effect of EO on SEC production at level 0.005% was observed when it was used in combination with nisin = 0.125 microL/mL. The significant (p < 0.05) synergistic effect of EO = 0.005% and nisin = 0.125 microL/mL was also observed as more reduction of hemolysis due to alpha-toxin than EO = 0.005% alone. Further, EO significantly (p < 0.05) prevented SEC production by S. aureus during the manufacturing process of a traditional Iranian white brined cheese (as a food model) even at its lowest concentration (5 microL/100 mL), in this study.

Background: Food born pathogenic bacteria are the most important agents of infections in humans, and food spoilage also results in economic losses in food industry. Objectives: The aim of this study was the evaluation of chemical components, total phenolic content, antioxidant and antibacterial activities of Artemisia dracunculus essential oil. Materials and Methods:The essential oil of Tarragon was analyzed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography/mass spectrometry (GC-MS). The antioxidant activity and total phenolic content were evaluated by bleaching of β-carotene and folin ciocalteu methods, respectively. The antibacterial effect of the essential oil was inspected on seven Gram-positive and negative bacteria using the microdilution method. Results: A total of 19 compounds were identified by GC-FID and GC-MS. The main compounds were methyl chavicol (84.83%), trans-ocimene (3.86%), z-β-ocimene (3.42%), limonene (1.79%) and α-pinene (0.57%). Total phenols were 10.16 ± 0.08 mg/g Gallic acid equivalent. The essential oil showed good antioxidant activity in bleaching of β-carotene method (50 ± 1.63%). The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) for essential oil ranged between 3.8 to 250 mg/mL, respectively. Conclusions: The essential oil of Tarragon might be replaced by synthetic antioxidant and preservatives in food industry.

The growth of Vibrio parahaemolyticus (at inoculation levels, 103 and 105 cfu/g) and Listeria monocytogenes (at inoculation level, 103 cfu/g) were investigated in salted fish fillets (brine salted at 4% NaCl) as affected by different concentrations of Zataria multiflora Boiss. essential oil (EO), nisin (N) and their combinations at 8C (and 4C only for L. monocytogenes) during 21 days. The growth of V. parahaemolyticus was inhibited at 8C (in control group) and reached <2 log10 cfu/g at the first day of study for inoculation level of 103 cfu/g. At inoculation level of 105 cfu/g, this inhibitory effect was significantly (P < 0.05) affected by adding EO. The significant inhibitory effect of N alone and synergistic inhibitory effect of EO with N were also observed during the study. For L. monocytogenes, the obvious significant inhibitory effect of EO and its combination with N was observed at 4C. Considering the organoleptic effect of the EO used in this study, the best inhibitory effects of EO in combination with N for V. parahaemolyticus and L. monocytogenes were obtained at combinations of EO = 0.405% and n = 0.75 µg/mL, and EO = 0.405% and n = 0.25 µg/mL, respectively. PRACTICAL APPLICATION The synergistic inhibitory effect of Zataria multiflora Boiss. essential oil and nisin on V. parahaemolyticus and L. monocytogenes, which was obtained in this study can improve the scope of essential oil function in food industry.