سحر روشنک

Globally, clinical mastitis (CM) is a significant disease in the dairy industry and has a tremendous economic impact because of the significantly reduced amount of milk production. Antibiotics are medicines used to treat infections, particularly those of bacterial origin. Misusing these common drugs leads to emerging resistance bacteria and public health concerns in human and animal medicine worldwide. Therefore, the use of natural alternatives with low effects is recommended. This article aims to evaluate the antibacterial activity of peptide nisin on mastitis bacteria and its synergistic effect with CLF36 peptide in vitro. Recombinant peptide nisin and CLF36 were obtained from previous research. The minimum inhibitory concentration (MIC) test was performed using the microdilution method on bacteria extracted from animal mastitis, such as Clostridium perfringens, Proteus mirabilis, Enterococcus faecalis, Salmonella typhimurium, Pseudomonas aeruginosa, and Listeria monocytogenes. This study showed that nisin and CLF36 alone had an inhibitory effect on all the studied bacteria in the 64-32 and 256-32 μg/ml concentration range, respectively. Also, the combination of nisin and CLF36 showed a general synergistic interaction for all used strains (FIC I < 0.5). This study demonstrated that combining these two peptides could reduce the risk of developing drug resistance by creating synergistic effects with a minimum concentration of each of the two peptides.

 It is essential to introduce new antimicrobials or to evaluate the synergistic effect of existing compounds as a therapeutic strategy against microbial strains resistant to one or more antibiotics. The aim of this study was to evaluate the antimicrobial activity and synergistic effect of lactoferrin chimera (cLF) in interaction with some common therapeutic antibiotics.

 The antimicrobial activity of cLF and the antibiotics including gentamicin, cefazolin, and ceftazidime were determined by the minimum inhibitory concentration (MIC) method and subsequently, the synergistic effect of this peptide with each of the mentioned antibiotics was checked against E coli, P. aeruginosa and S. typhi were investigated and the minimum fraction inhibitory concentration (FIC) was reported. Release of cytoplasmic materials, plotting of survival curves, and activity of peptides alone and in combination with antibiotics were evaluated, and bacterial cell morphology investigating was performed using scanning electron microscopy at MIC and FIC concentrations.

 The synergistic effect was observed in the combination of cLF with all antibiotics. The results showed that at FIC concentrations, material release from the cytoplasm and the number of surviving cells were significantly higher and lower than when peptides or antibiotics were used alone, respectively. The activity of peptides and antibiotics at FIC concentration was increasing and SEM images at this concentration showed severe membrane damage of bacterial cells.

 The use of cLF and antibiotics at FIC concentrations reduces the dose of both substances.

In this study, different concentrations of aqueous extract of Chubak root (at levels of zero, 0.5, 1, 1.5, and 2%) with different concentrations of rosemary essential oil nanoemulsion (zero, 0.5, 1, 1.5, and 2%) was used to optimize the production of biodegradable gelatin-based film. Test responses were statistically significant for all fitted regression models at 99% confidence level. To optimize film production, maximum transparency, contact angle, tensile strength, Elongation at Brake to the point of rupture and minimum solubility, swelling and vapor permeability were evaluating. After fitting the models, the results showed that the effect of aqueous extract of Chubak root and rosemary essential oil nanoemulsion on all responses was significant (P <0.05). Increasing the aqueous extract of Chubak root and nanoemulsion of rosemary essential oil increased the thickness, contact angle and Elongation at Brake to the point of rupture and decreased moisture content, vapor permeability, transparency, solubility, tensile strength and swelling. Based on the results of model prediction and comparison with experimental values, aqueous extract of Chubak root at a concentration of 2% and nanoemulsion of rosemary essential oil with a concentration of 0.77% were obtained as optimal values.

Usage of natural products like herbals, provide unlimited opportunities for novel and suitable additives. Mocheh can be used in fresh form or as an ingredient in soup and salad. This study was aimed to determine the antimicrobial and antioxidant activities of Mocheh (Lepidium draba) extract. The antimicrobial activity of Mocheh extract was tested against Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus and Aspergillus niger. The extract showed a strong antimicrobial activity with a concentration dependence and a broad antimicrobial spectrum for all tested microorganism species. The results showed that MIC of leaf extract of Lepidium draba on Aspergillus niger, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus was 128, 128, 128 and 128 mg/mL respectively. The results showed that MBC/MFC of leaf extract of Mocheh on the examined microorganisms was 256, 256, 256 and 256 mg/mL respectively. The values obtained for total flavonoid content and total phenolic contents were 22.13 µg/mL and 18.88 mg/mL, respectively. Measured value in the radical scavenging activity was IC50= 168/21 µL/mL. The results showed that Mocheh leaf aqueous extract is a novel source of natural antimicrobial and antioxidant agents for the food and pharmaceutical industries.

In this research, the chlorophyll content, total flavonoid content (TFC), total phenolic content (TPC) and antioxidant activity of aqueous extract of Dandelion was determined. In addition, the effect of aqueous extract of Dandelion, obtained by maceration, was tested on various food borne and food spoilage microorganisms. Antimicrobial activity of leaf extract of Dandelion was investigated using disk agar diffusion, well agar diffusion, minimum inhibitory concentration and minimum bactericidal/fungicidal concentration methods. The values obtained for TFC, TPC, chlorophyll a and b were 22.82 (µg/mL), 116.89 (mg/mL), 0.081 (mg/l) and, 0.063 (mg/l), respectively. The result of the radical scavenging activity was IC50= 68.81µl/mL. The results showed that MIC of leaf extract of Dandelion on Aspergillus niger, Salmonella typhimurium, Bacillus subtilis and Staphylococcus epidermidis was 512, 256, 256 and 64 mg/ml respectively. MBC for Aspergillus niger was more than 512, for Salmonella typhimurium, and Bacillus subtilis was 512, and for Staphylococcus epidermidis was 128mg/ml. In addition, the diameter of inhibitory growth zone in well diffusion method was more than disk diffusion. Generally, it can be stated that the aqueous leaf extract of Dandelion on Gram-positive bacteria showed more antimicrobial activity than Gram-negative bacteria, while there is no significant inhibition on mold. Based on the results of this study, Dandelion aqueous extract might be used as a natural agent to prevent the growth of food borne microorganisms, particularly, that cause food poisoning that leading to the reduction of gastroenteritis risk.

One of the problems with the processed meat products shelf life is the formation of yellow spots in sausages. The aim of this study was to isolate and identify the microbial agents causing yellow stain from sausage by molecular- and culture-based methods. For this purpose, 15 samples from yellow spot and separation areas of chicken sausages were sampled. A total of 44 colonies grown on the MRS, M17, YGC, and PDB culture medium were inoculated into pre-packaged cutting sausages to induce the yellow spot. Yellow spots appearance9 samples and they were characterized by both culture-based methods and sequencing of a 350 bp fragment from 16S rRNA V3 region and a 800bp fragment from 18S rRNA ITS4 region. The results of the culture-based and molecular assay showed that the main causes of the yellow spots in the chicken sausage packaged under vacuum were Enterococcus faecium, Enterococcus faecalis, Streptococcus faecium and Candida saitoana. In addition, one species of Enterococcus and one species of Candida were also identified at the genus level. Examination of yellow spotted samples also showed that the microorganisms that cause yellow spotting cause changes in pH, color indices L*, a* and b*, and syneresis compared to the control sample but the rate of change is only in the syneresis quantity and a* was significant.

Fermentation is one of the oldest techniques in food preservation, this process is defined as the biological activity of microorganisms to improve sensory, organoleptic and nutritional properties and produce a range of metabolites that inhibit the growth of unwanted microbial flora. As a result, fermented products have a shelf life substantially higher than raw materials and also have very beneficial effects on health. In this research, ginger in 4 and 8 % levels  and yogurt whey in 0 and 3 % levels, were added to the carrots and evaluated during of 0,4, 8, 16, 24 and 32 days of fermentation. The results showed that by adding 4% ginger, pH, mold and yeast count and L* index decreased, acidity, total count, lactic acid count, a* and b* color indexes and overall acceptance increased. In contrast, the addition of 8% ginger had a negative effect on the studied parameters and decreased the overall acceptance and enumeration of lactic acid bacteria. Addition of yogurt (3%) decreased pH, mold and yeast count and L* index, but increased acidity, total count also color indices a* and b* and overall acceptance. In the non-yogurt and non-ginger sample from the beginning to the end of the storage period, pH, total count and mold and yeast counts increased steadily, and overall acidity and acceptance decreased. Whereas in the samples containing ginger and yogurt, the pH and count of mold and yeast decreased as the fermentation time increased to the 16th day and overall count increased, lactic acid bacteria, acidity and total acceptance. According to the results of this study, using 4% ginger, 3% yogurt and 16 days fermentation time to increase shelf life and lactic acid bacteria and improve the sensory characteristics of fermented carrots.

Saffron is the most expensive agricultural product in the world and Iran is the largest saffron producer in the world. Saffron contamination in different stages of the production process, in addition to quality loss leads to reducing credit in the global market and exporting. Therefore, it is necessary to select an appropriate method for inactivation the microbial flora of saffron. Among the common methods that used to inactivation the microorganisms, cold plasma is due to the potential benefits such as non-toxic nature, low operational costs, and a significant reduction in water consumption during decontamination, and the possibility of its use for a variety of food products has attracted much attention. Plasma is a state of ionizing gas, including ions, electrons, ultraviolet rays, and reactive species such as radicals, atoms and molecules that can ignite, which can inactivate microorganisms. in this research, cold plasma was produced using two types of gas including nitrogen and air, and the effect of plasma radiation at 0, 3, 6, 9 and 12 minutes on the chemical and microbial (Escherichia coli, Enterococcus faecalis, Mold and Yeast) properties of saffron were investigated. The results of this study showed that germicidal effect of nitrogen plasma was lower than air plasma and the plasma exposure time had a significant effect on reduction of microbial load and by increasing the time of plasma exposure, the inactivation of microorganisms increased. The maximum microbial reduction was observed in 12 minutes. Maximum reduction in microbial load was observed at 12 minutes and 18 kilovolt voltage, which reduced the population of Escherichia coli, Enterococcus faecalis, mold and yeast by 2/69, 2/48, 1/95 log cycle respectively, However, with increasing radiation time, the amount of crocin, picocrocin and safranal decreased (p˂0.05). Reduction of crocin, safranal and picocrocin in 12 minutes was 6/01, 4/04, 5/44%, respectively.

In recent years, due to the common use of commercial antimicrobial drugs in the treatment of infectious diseases, the resistance to one or more antibiotics is increasing. The use of Lepidium drabaas an herbal plant in Iran, has a long history. The aim of this study was to evaluate the anti-microbial activity of Lepidium drabaextract on some of microorganisms causing infection (in vitro).

In this experimental study, the extract of Lepidium drabaaimed by maceration method. Extraction efficiency was calculated based on dry weight. The antimicrobial effect of the Lepidium drabaextract was studied by evaluated minimum inhibitory concentration, minimum bactericidal/fungicidal concentration, and determination of the zone of microbial growth inhibition (disc diffusion agar and well diffusion agar) on Escherichia coli, Salmonella typhi, listeria innocua, Staphylococcus epidermidis and Candida albicans.

The minimum inhibitory concentration and the minimum fungicidal concentration of aqueous extract of Lepidium drabawere 64 and 128 mg/ml for Candida albicans (the most sensitive strain to extract), respectively. The minimum inhibitory concentration of extract for Escherichia coli, Salmonella typhi, Listeria innocua, and Staphylococcus epidermidis was 256, 256, 128 and 128 mg/ml, respectively. The minimum bactericidal concentrations of the extract of Lepidium drabafor these strains were 256,256, 128, and 256 mg/ml, respectively. For all infectious strains, analysis of data at 5% significance level showed that, by increasing the concentration of the extract, the diameter of zone of microbial growth inhibition (disk diffusion agar and well agar diffusion) had increased. The results showed that the diameter of zone of microbial growth inhibition in the well agar diffusion method was higher than the disk agar diffusion method.

The extract of the Lepidium drabahad antimicrobial effecton all strains. The most susceptible and resistant to this extract were candida albicans and Escherichia coli, respectively. It is recommended that further studies be conducted in vitro and animal model to use this plant for treating infectious diseases and control the growth of pathogenic microorganisms

Sheng (Tragopogon graminifolius) is belongs to the Asteraceae family. In traditional medicine, Sheng is used to treat gastric ulcers, liver dysfunctions, preventing bleeding, pulmonary infections, and wound healing. In this study the antibacterial effect of Sheng extract on Staphylococcus epidermidis, Bacillus subtilis, Escherichia coli and Salmonella typhi was evaluated in laboratory conditions. In this experimental study, antimicrobial activity of Sheng extract on Staphylococcus epidermidis, Bacillus subtilis, Escherichia coli and Salmonella typhi was evaluated by disc diffusion agar and well diffusion agar (diameter of the inhibition zone) methods. Minimum inhibitory concentration (broth microdilution and Triphenyl tetrazolium chloride reagent) and minimum bactericidal concentration (pure plate) of Sheng extract were determined and reported. The results showed that the zone of inhibition diameters increased with increasing concentrations of the extract of Sheng. The highest zone of inhibition (22mm) by well diffusion agar method was related to Staphylococcus epidermidis. The minimum inhibitory concentration of aqueous extract of Sheng for Staphylococcus epidermidis, Bacillus subtilis, Salmonella typhi and Escherichia coli was obtained 64, 256, 256, and 256, respectively. Sheng extract had an appropriate antibacterial effect on the strains studied. It is recommended that further studies be conducted in vitro and in vivo to use this plant to treat infectious diseases and control the growth of pathogenic microorganisms.

Dandelion with the scientific name Taraxacum pseudocalocephalum belongs to the Asteraceae family. The aim of this in vitro study was evaluated the effect of leaf extract of dandelion on Candida albicans, Staphylococcus aureus, Bacillus cereus, Listeria innocua, Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa and comparing itʼs effect whit common antibiotics. In this research, leaf extract of dandelion was obtained by Maceration. Antimicrobial activity of leaf extract of dandelion was investigated using disk diffusion methods, well distribution in agar, minimum inhibitory concentration (MIC) (broth microdilution) and minimum bactericidal/fungicidal concentration (MBC or MFC). results of MIC of leaf extract of dandelion on Candida albicans, Staphylococcus aureus, Bacillus cereus, Listeria innocua, Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa was 128, 128, 256,256,256,256 and 512 respectively. The most resistant strain to the aqueous leaf extract of the dandelion was the gram-negative bacteria of Pseudomonas aeruginosa. The result showed that the diameter of inhibitory growth zone in well diffusion agar method was more than disk agar diffusion and the strains showed bigger zone in lower concentration. It can be stated that the aqueous leaf extract of dandelion on gram-positive bacteria and candida albicans showed more antimicrobial activity than gram negative strains, generally. According to the results of this study, further research on the antimicrobial compounds of the dandelion is suggested to be used in the treatment of infectious diseases.

In this study, the antimicrobial effect of HPEO was evaluated on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans through the methods of disk diffusion agar, well diffusion agar, minimum inhibitory concentration (micro dilution broth), and minimum bactericidal/fungicidal concentration. Antioxidant potential and total phenolic content were examined through the method of 2,2-diphenyl-1picrylhydrazyl (DPPH) and Folin-Ciocalteu method, respectively. Plantago major seed mucilage (PMSM) edible coatings were prepared at four different concentrations of the HPEO, including 0, 1, 1.5 and 2 percent. The control and the coated beef samples were analyzed periodically for microbiological (total viable count, psychrotrophic bacteria, Escherichia coli, Staphylococcus aureus and fungi), chemical changes (thiobarbituric acid, peroxide value and pH) and sensory attributes (color, odor and total acceptability) of the beef slices coated with pure PMSM at 4°C for 15 days (0, 3, 6, 9, 12 and 15). The minimum inhibitory concentration of the HPEO varied from 0. 5 mg/ml to 4 mg/ml. The total phenolic content (TPC) and antioxidant power were equal to 9.50 mg GAE/g and 57.25 ± 0.2 mg/ml, respectively. PMSM extended the microbial shelf life of beef by 3 days, whereas the PMSM incorporated with (1, 1.5 and 2) HPEO resulted in a significant shelf life extension of the beef by 3, 6 and 9 days, respectively, as compared to the control samples. Thus, PMSM containing HPEO could be used as an active packaging to maintain quality and extend the shelf life of the beef at 4◦C.