Hossein Tajik

CHEMICAL COMPOSITION OF ESSENTIAL OILS IN ZATARIA MULTIFLORA BOISS. FROM DIFFERENT PARTS OF IRAN AND THEIR RADICAL SCAVENGING AND ANTIMICROBIAL ACTIVITY

The objective of the study was to characterize the chemical constituents, antioxidant and antibacterial properties of five ecotypes of Zataria multiflora Boiss. essential oil with respect to main phytogeographic grown towns in Iran. Our investigation showed that the plants had essential oil yield ranging from 1.59+/-0.86% to 0.99+/-0.29% v/w. There were qualitative similarities among the oils from different origins, whereas the amounts of some components were varied. From different samples, 34, 34, 32, 29 and 53 various compounds were identified, representing 98.32%, 97.77%, 99.5%, 98.38% and 96.54% of total oils, respectively. The highest oxygenated monoterpens value in this study stood at 72.99%. Moreover, thymol, a phenolic compound of oxygenated monoterpens, was the most abundant component in GC/MS ranging from 27.05% to 64.87%. In the DPPH antioxidant assay, all samples exhibited a remarkable activity with a higher degree of IC(50)=19.7+/-0.7 microg/ml almost similar to BHT (18.1+/-0.4 microg/ml). Escherichia coli O157:H7 was the most resistant and Candida tropicalis was the most vulnerable organisms with MICs of 16 and 0.062 mg/ml, respectively. In conclusion, it seemed that geographical variation might have influenced the oil compounds either quantitatively or qualitatively.

Preparation of Chitosan from Brine Shrimp (Artemia urmiana) Cyst Shells and Effects of Different Chemical Processing Sequences on the Physicochemical and Functional Properties of the Product

Chitosan (CS) was prepared from Artemia urmiana cyst shells using the same chemical process as described for the other crustacean species, with minor adjustments in the treatment conditions. The influence of modifications of the CS production process on the physiochemical and functional properties of the CS obtained was examined. The study results indicate that Artemia urmiana cyst shells are a rich source of chitin as 29.3-34.5% of the shell’s dry weight consisted of this material. Compared to crab CS (selected as an example of CS from a different crustacean source) Artemia CS exhibited a medium molecular weight (4.5-5.7 ×105 Da), lower degree of deacetylation (67-74%) and lower viscosity (29-91 centiposes). The physicochemical characteristics (e.g., ash, nitrogen and molecular weight) and functional properties (e.g., water binding capacity and antibacterial activity) of the prepared Artemia CSs were enhanced, compared to control and commercial samples, by varying the processing step sequence.

Chloramphenicol residues in chicken liver, kidney and muscle: A comparison among the antibacterial residues monitoring methods of Four Plate Test, ELISA and HPLC

There are many concerns about safety of food contaminated with antibacterial residues. This study was designed to investigate the occurrence of chloramphenicol (CAP) residue in broiler chickens tissues, namely liver, kidney and muscle. One hundred and sixty broiler chickens carcasses were collected from three provinces of Iran. Four Plate Test (FTP), ELISA and HPLC were used to qualify and quantify the contamination of the samples with CAP. The results of FPT revealed that up to 17.5% of the samples were contaminated with the antibiotic. The ELISA assay showed that out of 28 positive samples in FPT, 22 liver, 21 kidney and 14 muscle samples were positive for CAP. ELISA analyses demonstrated that the minimum and maximum levels of 0.54 and 155.2 ng/g were detected in the kidney and liver, respectively. HPLC analyses confirmed the ELISA findings although the level of contamination was lower than that of ELISA. These data showed that despite the prohibition of CAP application in food animals including poultry, the CAP residue was detectable indicating an illegal use of this antibiotic. Our findings also demonstrated the application of sensitive and more specific analytical assays in screening and quantitation of CAP residues in food products.

Effectiveness of Zataria multiflora Boiss essential oil and grape seed extract impregnated chitosan film on ready‐to‐eat mortadella‐type sausages during refrigerated storage

BACKGROUND The effectiveness of chitosan films containing Zataria multiflora Boiss essential oil (ZEO) (5 and 10 g kg(-1) ) and grape seed extract (GSE) (10 g kg(-1) ) on lipid oxidation and microbial (lactic acid bacteria, aerobic mesophiles and inoculated Listeria monocytogenes) characteristics of mortadella sausage at 4 °C for 21 days was evaluated. The release of total phenolics (TPs) into sausage was also assessed. RESULTS All films exhibited antibacterial activity against L. monocytogenes on agar culture media. Chitosan films containing ZEO were the most effective on the growth of bacteria. The growth of L. monocytogenes was significantly inhibited by ZEO-GSE containing films especially during storage of the sausages for 6 days. Aerobic mesophiles and lactic acid bacteria were the most sensitive and resistant groups to films by 0.1-1.1 and 0.1-0.7 log cycles reduction, respectively. Sausages wrapped by 10 g kg(-1) GSE + 10 g kg(-1) ZEO films had the lowest degrees of lipid oxidation, which was 23% lower than the control. The TPs of ZEO films decreased to zero after 6 days, whereas TPs of GSE films followed a slight decrease during the storage. CONCLUSION Antimicrobial/antioxidant chitosan film could be developed by incorporating GSE and ZEO for extending the shelf life of mortadella sausage.

A novel dispersive micro solid phase extraction using zein nanoparticles as the sorbent combined with headspace solid phase micro-extraction to determine chlorophenols in water and honey samples by GC–ECD

This study presents a new technique, dispersive micro solid phase extraction (DMSPE) combined with headspace solid phase micro-extraction (HS-SPME) for extraction and determination of chlorophenols (CPs) in water and honey samples using a Gas Chromatography-Electron Capture Detector (GC-ECD). Zein nanoparticles were made by liquid-liquid dispersion and applied for the first time as the sorbent phase in DMSPE. In the proposed DMSPE-HS-SPME method, 1% w/v of ethanolic zein solution was added to an aqueous sample and then a dose of the in-situ generated zein nanoparticles was applied to a pre-concentration of target analytes. Thermal desorption of analytes was performed after the isolating sorbent phase, and then HS-SPME was applied for enrichment prior to introducing to gas chromatography. All the important parameters influencing efficiency of the extraction process such effects of salt, pH, sorbent concentration, temperature, sorbent solution volume in DMSPE procedure, extraction temperature, extraction time, desorption temperature and time in the HS-SPME procedure were investigated and optimized. Results showed that under optimum extraction conditions, detection limits (signal to noise ratio=3) were in the range of 0.08-0.6 ng mL(-1) and evaluations for relative standard deviations (RSDs %) were between 6.62% and 8.36%.

Synergistic antibacterial activity of the essential oil of Cuminum cyminum L. seed and nisin in a food model

Aims:  To investigate effects of various concentrations of the essential oil of Cuminum cyminum L. seed alone and in combination with nisin on survival of vegetative forms of Bacillus cereus and Bacillus subtilis in a food model (commercial barley soup) and their ultrastructure.

Effects of Mentha longifolia L. Essential Oil and Nisin Alone and in Combination on Bacillus cereus and Bacillus subtilis in a Food Model and Bacterial Ultrastructural Changes

In the face of emerging new pathogens and ever-growing health-conscious customers, food preservation technology remains on the top agenda of food industry. This study was aimed at determining the effects of the essential oil of Mentha longifolia L., alone and in combination with nisin, on Bacillus cereus and Bacillus subtilis at 8°C and 25°C in a food model (commercial barley soup) during 15 days. The essential oil alone at 8°C inhibited bacterial growth significantly compared with the control (p < 0.05). However, at 25°C, none of the concentrations of the essential oil alone showed inhibitory effect on bacterial growth. At 8°C, the combination effect of the essential oil and nisin on bacteria was noted at 0.25 μg mL(-1) for nisin and 0.05 μL mL(-1) for the essential oil (p < 0.05). The combination of nisin and the essential oil demonstrated significant inhibitory effects on the vegetative forms of bacteria at 25°C, although it was comparable to that of nisin alone at the same concentrations. Electron microscopy studies revealed a great deal of damage to B. cereus treated with a combination of nisin and the essential oil. However, the combination of nisin with the essential oil led to a complete destruction of cell wall and cytoplasm of vegetative cells of B. subtilis.

Biochemical properties and microbial analysis of honey from North-Western regions of Iran: Seasonal effects on physicochemical properties of honey

In the present study, physicochemical properties (pH, ash, commercial glucose, starch, reducing sugars and moisture) and microbial (yeast and enterobacterial) contaminations of 263 honey samples from North-western regions of Iran were evaluated in a 2 year period in different seasons of 2010 and 2011. Levels of reducing sugars and sucrose showed significant seasonal differences, with the highest levels observed in summer samples. No commercial glucose or starch was detected in any of the samples; but levels of reducing sugars and sucrose content of 1.52 and 6.84% samples were unacceptable, respectively. Moisture, ash content (0.4 ± 0.01%) and pH values (4.44 ± 0.02) of all samples were in the required standard range and did not significantly vary in different seasons. Of all the samples evaluated, only seven samples (2.66%) contained yeast, and two samples (0.76%) were contaminated with bacteria from family Enterobacteriaceae (2 samples with both contaminations). None of the isolates were found to be of major pathogenic importance.

The Role of Nisin, Monolaurin, and EDTA in Antibacterial Effect of Rosmarinus Officinalis L. and Cinnamomum Zeylanicum Blume Essential Oils on Foodborne Pathogens

Abstract In this study, the role of nisin, monolaurin and EDTA in strengthening antibacterial effect of the Rosmarinus officinalis L. and Cinnamomum zeylanicum Blume essential oils were tested against foodborne pathogens including Escherichia coli, Salmonella typhimurium, Listeria monocytogenes and Staphylococcus aureus. The essential oils extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry (CG-MS). For determining antimicrobial effects of the essential oils in corporation with nisin, monolaurin and EDTA, agar disk diffusion and broth micro dilution susceptibility tests were used. According to GC-MS analyses, 15 and 14 components were identified for rosemary and cinnamon essential oils that representing 95.1 % and 94.25 % of total components, respectively. In the case of rosemary essential oil, 1,8-cineole (24.3 %), α-pinene (22.8 %), and camphor (12.1 %) were determined as the main volatiles. On the other hand, cinnamaldehyde (79.74 %) was determined as the major compound for cinnamon essential oil. According to antimicrobial activity tests, L. monocytogenes was found as the most sensitive microorganism. It is followed by S. aureus, E. coli, and S. typhimurium, respectively. In general, EDTA made the weakest effect on the MIC and MBC values of the essential oils. On the other hand, nisin made the most promising effect on the MIC and MBC values of the essential oils. In conclusion, using monolaurin, nisin and EDTA together with essential oils led to increases the antibacterial effect of essential oils against both Gram positive and Gram negative tested bacteria.

Haematological changes of cats with Toxoplasma gondii -specific antibodies

The purpose of this study is to access the usefulness of haematological parameters in diagnosing of chronic toxoplasmosis in cats. Antibodies of Toxoplasma gondii were detected in 50 cats using an enzyme-linked immunosorbent assay. Immunoglobulin M (IgM) and immunoglobulin G (IgG) were measured with the cutoff point for T. gondii considered to be 1:64. Fifteen (30%) of the cats were found to be seropositive. No statistically significant difference was found amongst different age groups, but the male cats showed significantly higher antibody titres than female cats. A significant positive correlation was found between IgM and IgG of the cats. Comparison of haematological data between two groups of the cats (IgM <1/64, n = 35; IgM ≥1/64, n = 15) showed that packed cell volume (PCV), red blood cell (RBC) and monocyte values in cats with higher IgM titres were significantly higher than cats with lower IgM. It is suggested that in cases with higher values of PCV, RBC and monocyte in routine complete blood count profile of apparently normal cats, toxoplasmosis should be considered. Further studies with more cases are needed to ensure the diagnostic values of these measured parameters.