No abstract

No abstract

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.

No abstract

Background: Antibiotics are extensively used as therapeutic, prophylactic and growth promoting agents in the poultry industry. However, their widespread use resulted in the presence of residuals in poultry meat and offals potentially leading to public health hazards. The present research was done to assess the distribution and concentration of residual antibiotics in chicken meat and liver samples. Methods: Ninety chicken meat and liver samples were collected and transferred to laboratory. Presence and concentration of residual tetracyclines, sulfonamides and trimethoprim were assessed using the Liquid Chromatography -Tandem Mass Spectrometry technique. Results: There were no detectable concentrations of tetracyclines in all studied samples. Twenty-eight out of 90 (31.11%) raw meat and 31 out of 90 (34.44%) liver samples were positive for residual sulfonamides. Prevalence of positive meat and liver samples for residual sulfachloropyrazine, sulfadimethoxine and trimethoprim antibiotics were 16.66%, 5.55% and 8.88% and also16.66%, 5.55% and 11.11%, respectively. Sulfathiazole residue was only detected in 1.11% of chicken liver samples. Chicken liver samples had the higher concentrations of all detected residual sulfonamides. Sulfachloropyrazine had the highest concentration in raw chicken meat (20.8±1.88 µg/kg) and liver (24.4±1.54 µg/kg) samples, while sulfadimethoxine had the lowest (6.05±0.25 µg/kg and 9.26±0.36 µg/kg, respectively). Conclusion: All detected concentrations of residual sulfonamides were lower than Maximum Residue Limits (MRLs). Presence of residual antibiotics represents a serious public health treat regarding the occurrence of antibiotic resistant bacterial strains. LC MS/MS has been introduced as a sensitive and specific technique for monitoring and surveillance of residual antibiotics in chicken samples.

Increasing consumer demand for seafood, combined with concern over the health of our oceans, has led to many initiatives aimed at tackling destructive fishing practices and promoting the sustainability of fisheries. So, our aim was to develop a PCR-based technique for checking authenticity of fish fillets supplied in Tabriz (Iran). In present study, about 80 samples of frozen fish fillet with general trademarks including south fillet, excellent fillet and 40 samples of Javelin grunter fillet and Scomberomorus commerson fillets were collected from different chain markets all over the Tabriz. Lot Tolerance Per-cent Defective (LTPD) method was used in collecting the samples which is the low errors. Our research showed a higher rate of misbrandingand misla-beling found in markets with general names (85%) and specified names of Javelin grunter and Scomberomorus commerson (40%). Based on present study, the capacity of shark is high in mislabeling and fraud because of their situation in making steaks and fillet, low price in compared with other spe-cies and religious limitations.