Aim:Shiga toxigenic Escherichia coli (STEC) strains as emerging groups of foodborne pathogens are responsible for most foodborne illnesses. The aim of this study was to determine the antibiotic resistance pattern in STEC isolated from traditional milk products and their molecular characterization.Materials and Methods:A total of 116 samples were randomly purchased from local markets in Kashan, Iran, and evaluated for the occurrence of STEC by culturing and molecular methods. The antibiotic resistance of obtained isolates was determined by Kirby Bauer method. Furthermore, isolates were assayed for the presence of Shiga toxins (stx1 and stx2) and intimin gene (eae).Results:The incidence of E. coli in 60 ice cream, 30 yoghurt, and 26 cheese samples was 8.33%, 10%, and 11.54%, respectively. The findings showed that 11 out of 11 (100%) E. coli had both stx1 and stx2 while eae gene was not found in E. coli isolated of traditional milk products. For E. coli strains carrying stx1 and stx2, highest antibiotic sensitive levels were related to trimethoprim/sulfamethoxazole, norfloxacin, chloramphenicol, and ciprofloxacin, respectively.Conclusion:The results showed relationship between the presence of virulence factors and antimicrobial resistance. These results can be used for further studies on STEC as an emerging foodborne pathogen.
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.
This research was aimed at investigating the antioxidant and antibacterial activity of Bunium persicum, Eucalyptus globulus, and rose water on multidrug-resistant Listeria species. The antibiotic resistance of Listeria spp obtained from seafood samples were determined by the Kirby-Bauer method. The antioxidant and antibacterial activity of the essential oils and extracts were evaluated using ferric reducing antioxidant power and microdilution methods, respectively. A total 2 samples (1.88%) were positive for Listeria spp. L monocytogenes was found to be resistant to ampicillin, amoxicillin/clavulanic acid, penicillin, vancomycin, and kanamycin. B persicum essential oil showed the greatest antioxidant activity (248.56 ± 1.09 µM Fe2+/g). The E globulus essential oil showed consistently strong antimicrobial activity against L monocytogenes and L grayi, while rose water showed no antimicrobial activity against any of the tested bacterial strains. The results showed that after adding the B persicum and E globulus essential oils to bacteria, the cell components’ release increased significantly.
Purpose
The purpose of this study is to evaluate antimicrobial activity of chitosan incorporated with lemon and oregano essential oils on broiler breast meat during refrigerated storage.
Design/methodology/approach
In this experimental study, antibacterial effect of lemon and oregano essential oils was measured using the microdilution method for four foodborne pathogenic bacteria. The effect of 0.5, 1 and 2 per cent (Wt./Vol.) essential oils with chitosan 2 per cent on microbial quality of broiler breast meat (slaughter age: 42 days), up to 9 days’ storage time in 4 ± 1°C temperature was evaluated. Also, organoleptic characteristics of meat samples in certain storage time were examined.
Findings
The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for lemon and oregano essential oils ranged between 1.41 and 11.25 and 2.81 and 22.5 mg/mL, respectively. In the treatment groups, A decrease in total mesophilic bacterial count (TMBC) was observed up to sixth day, but TMBC increased on the ninth day. Decrease in lactic acid bacteria, Enterobacteriaceae, mold and yeast in the treatment groups was observed compared with the control group up to the ninth day (p < 0.01). Overall, chicken meat containing 1 per cent lemon essential oil with chitosan had a greater acceptance rate (p < 0.01).
Originality/value
In recent years, active packaging containing essential oils have been used to maintain the quality and increase the shelf life of various types of meat, chicken, fish, shrimp, fruits, etc. Therefore, it can be suggested that using chitosan in combination with the aforementioned essential oils in combination might increase shelf life of chicken meat during refrigerated storage.
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