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The control of bacterial diseases of fish has always been one of the most important problems of aquaculteriets in recent years. One of these problems is bacterial resistance. Using antibiotics can cause problems for consumers. Therefore, the use of new antimicrobial agents with minimal complications is common. In the present study, using the acid-thermal method, the bentonite structure was modified and the chitosan and bentonite hybrids were modified in the stage of development. The structure of the compounds was studied using the Infrared Fourier Transform Spectrometry (FTIR), Surface Electron Scanning Microscopy (FE-SEM) and X-ray diffraction spectroscopy (EDX). Antimicrobial activity of two types of modified bentonite on gram negative bacterium Aeromonas hydrophila was studied in vitro using two methods of disk diffusion and microdilution. The results of the disc diffusion method showed that the antimicrobial compounds produced had antibacterial properties in experimental conditions against the Aeromonas hydrophilia bacteria. Antimicrobial activity (MIC and MBC) was determined using microdilution and clonal counting in Agar culture medium. The results showed that the modified compound with the acidic method had MBC of 28.57 and 14.28 mg / L for Aeromonas hydrophila bacteria in 10 minutes and 30 minutes. For chitosan and modified bentonite composite, MBC was 14.28 mg / ml for Aeromonas hydrophila bacteria in 10 and 30 minutes. The results of this study showed that modified bentonite and composite compounds have strong antimicrobial effects and can remove pathogens in laboratory conditions and can be used as new compounds to control pathogens in breeding systems.

 

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Introduction: Nanotecnology could solve most of problem of biomedical and cause improve in health and pharmacology field. Also this industrial cause to eliminate food pathogenic bacteria.increase of food pathogenic bacteria and resistance them to different antibiotics caused usage of nanotechnology by researchr and pharmacologiests. Material and Methods:In this reseach is studied antimicrobial effect of nanoparticles of silver,TiO2 against on food pathogenic bacteria such as Staphylococcus aureus PTCC 1431 and Listeria monocytogenes by determination MIC and MBC. Result: Silver nanoparticle was synthezied with 103 nm of size and consentraion of 1 mili molar,nano TiO2 with 21 nm of size and consentrain of 1% have antimicrobial effect against on Staphylococcus aureus PTCC 1431 Listeria monocytogenes . Conclusion: Since that antimicrobial activity of silver ,TiO2 nanoprticles against on food pathogenic bacteria (Staphylococcus aureus PTCC 1431 and Listeria monocytogenes) is proved, is suggested to packaging antimicrobial food. Keywords: Silver nanoparticle,TiO2,,Antimicrobial effect, Staphylococcus aureus PTCC 1431 Listeria monocytogenes

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Nowadays, finding new resources of vegetal antioxidants in order to use them in food (as an additive or alternative with artificial antioxidants) is an important research subject in the field of food science and technology. In this research methanolic extracts of green and black raspberry leaves were examined in antioxidant properties, total phenolic content (TPC) and antimicrobial activity against Escherichia coli, Staphylococcus aureus, Entherococcus faecalis, Salmonella typhimurium, Yercinia enthrocolitica and Shigella dysenteria. then, three concentrations of each extract (200, 400, and 600 ppm) were applied in free antioxidant-purified soybean oil. The oils were kept in 60° C for a period of one month. After storage, Peroxide index, Iodine index, and Acidity value of oil samples were determined. According to the results, in all concentration of extracts, green leaves extract (GLE) had more antioxidant activity (0.7- 87%) and TPC (103±0.1 mg/g dry matter) significantly than black leaves extract (BLE). In antimicrobial activity, GLE in the minimum concentration of 7.12 mg/ml had an antimicrobial effect on Staphylococcus aureus and in the minimum concentration of 28.5 mg/ml inhibited the growth of Salmonella typhimurium, Yercinia enthrocolitica. But BLE did not show any effects on growth of investigated microbes. In the quality tests of oil samples, with an increase in the concentration of GLE, acidity, Iodine index, and peroxide index increased significantly. At the end, it was concluded that oil samples containing 200 ppm, had better quality and stability than samples containing 200 ppm Propyl Gallate (market soybean oil).

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Hyssopus officinalis and frankincense (Boswellia carteri), as valuable medicinal herbs, are widely used in traditional medicine. Due to the increased resistance of pathogenic microorganisms to antibiotics and increasing of treatment costs, attentions has been focused to compounds of natural origin. In this study, Hyssop and Frankincense oils were extracted separately by water distillation. The essential oils components were identified by GC/MS. Determination of inhibition zone diameter and minimum inhibitory concentration were performed by disk agar diffusion and macro dilution methods, respectively. Wells with no discoloration were used to detect the minimum bactericidal (fungicidal) concentration. In this research, 24 and 22 compounds were identified in Hyssop and Frankincense, respectively. The main component of Hyssop oil was cis-3-pinanone (%28.2), and the main component of Frankincense oil was α- pinene (%22). Both Hyssop and Frankincense oils had the highest effect on Staphylococcus aureus and Bacillus cereus, and the lowest growth zone diameter was related on Escherichia coli and Pseudomonas aeruginosa. Also, it was found that the Candida albicans was more sensitive than Aspergillus niger against both essential oils (p<0.05). The results showed that plants are rich in secondary products such as terpenoids, alkaloids and flavonoids, most of which have antimicrobial activity.

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 Medicinal plants have been used for its medicinal attributes from several thousand years ago. Eucalyptus is one of these plants which the antimicrobial effects has long been used to treat a cold and influenza in most parts of the world. The aim of this experimental study was to evaluate the antibacterial activity of Eucalyptus globulus essential oil (EGEO) in 4 ways: disc diffusion agar, well diffusion agar, microdilution broth and minimum bactericidal concentration on a number of strains pathogens and the cause of food spoilage in vitro. The sensitivity profile of microorganisms against the EGEO (disc diffusion agar) is as follows form the most resistant to the most sensitive: Salmonella typhi > Escherichia coli > Pseudomonas aeruginosa > Bacillus subtilis > Streptococcus pyogenes > Staphylococcus aureus. The mean inhibition zone in well diffusion agar was equal to 18.62 mm against Gram-positive bacteria. The mean inhibition zone in well diffusion agar was equal to 11.93 mm against Gram-negative bacteria. The results showed that the minimum inhibitory concentration of EGEO for Salmonella typhi, Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, Streptococcus pyogenes and Staphylococcus aureus was 128, 64, 64, 32, 16 and 8 mg/ml respectively. The minimum bactericidal concentration for microorganisms was 512, 256, 128, 128, 32 and 16 mg/ml respectively. It is recommended that additional tests be performed to use EGEO for use as a natural preservative in the food and pharmaceutical industry.

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Hyssopus officinalis is a belongs to Lamiaceae family and a herb widely growing in Iran .The aim of this experimental study was to evaluate the antimicrobial effect of Hyssopus officinalis extract in 4 ways: disc diffusion agar, well diffusion agar, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) on some microorganism pathogen “in vitro”. The results showed that with increasing the concentration of Hyssopus officinalis extract, the inhibition zone diameter increased. The highest inhibition zone with a diameter of 19.70 mm was observed at a concentration of 80 mg/ml for Gram-positive bacteria Staphylococcus aureus. At a concentration of 80 mg/ml, the ethanolic extract of Hyssopus officinalis showed the lowest inhibition zone observed with a diameter of 13.30 for Escherichia coli. The results showed that the MIC of Hyssopus officinalis extract for Pseudomonas aeruginosa, Escherichia coli Staphylococcus aureus and Listeria innocua was 64, 64, 8 and 16mg/ml respectively. The MBC for 128, 128, 32 and 64 mg/ml respectively. The data obtained in this study confirmed that Hyssopus officinalis extract inhibit growth some microorganism pathogen “in vitro”.

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Malva sylvestris belongs to Malvaceae familyThe biological active compounds of Malva sylvestris describe probably it’s biological activities and therapeutic activity. The purpose of this study was to investigate the antibacterial effect of Malva sylvestris on some pathogenic bacteria “in vitro”.In this study, the extraction was carried out by the maceration method. The pour plate method and disk diffusion method were adopted to determine the susceptibility of the pathogenic strains against Malva sylvestris extracts. The broth microdilution and fractional inhibitory concentration index (FICI) were employed to determine antimicrobial effect. The minimum bactericidal concentration was measured by pour plate method. The concentration 100 mg/ml of the ethanolic extract showed the best result on Streptococcus pyogenes and Staphylococcus aureus (p<0.05).  Enterobacter aeruginosa was resistant to most of the aqueous and ethanolic Malva sylvestris extracts. Minimum inhibitory concentration of the ethanolic extract of Malva sylvestris for Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli and Enterobacter aeruginosa were 8, 8, 64 and 64 mg/ml, respectively and the aqueous extract were 16, 32, 128, and 128 mg/ml, respectively.The ethanolic extract of Malva sylvestris had more inhibitory effect than the aqueous extracts on pathogenic strains. Furthermore, aqueous and ethanolic Malva sylvestris extracts showed greater inhibitory effect on gram-positive bacteria in comparison with gram-negative bacteria.

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In this study, aqueous and ethanolic extracts of Lippia citriodora were obtained by the Maceration method. The total phenol content, total flavonoid content, antioxidant activity (based on DPPH and ABTS free radical scavenging activity and FRAP methods) and antimicrobial effect (based on disc diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal/fungicidal concentration) of the extracts were investigated. Total phenols (72.55 vs. 60.32 mg GAE/g) and flavonoid (40.5 vs. 32.25 mg QE/g) contents of the ethanolic extract were higher compared to the aqueous extract. Antioxidant activity results revealed that the ethanolic extract was more effective in scavenging DPPH free radicals (45.4 mg/ml vs. 52.5 mg/ml) and ABTS free radicals (41.48 mg/ml vs. 47.65 mg/ml) with a greater reducing power (15.1 μmol Fe/g vs. 12.2 μmol Fe/g) in comparison to the aqueous one. Antimicrobial effect of the extracts against pathogenic microorganisms (Escherichia coli, Salmonella typhi, Staphylococcus aureus, Streptococcus pyogenes, and Candida albicans) showed that Gram-positive organisms were generally more sensitive than the Gram-negative ones, and the antimicrobial activity was more pronounced in the presence of the ethanolic extract. Based on the results, the aqueous and ethanolic extracts of L. citriodora could be introduced as natural preservatives to control the oxidation reaction and the growth of pathogenic microorganisms.

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In recent years, the use of natural antimicrobial compounds in food has attracted the attention of consumers and researchers, the two main reasons for this is the excessive and incorrect use of antibiotics due to the selective pressure it exerts on microorganisms It creates resistance to antibiotics, thus increasing a group of microorganisms, including pathogens in food, which are not only resistant to antibiotics but also resistant to food processing and storage methods. Increasing public awareness of the potential negative effects of artificial preservatives on human health versus natural additives has led many researchers to focus more on the use of natural preservatives in food. Many compounds obtained from natural sources have antimicrobial properties and can be used to maintain food safety. Today, the use of food preservatives has become a necessity that plays an important role in the storage and transportation of food. The goals of adding preservatives to foods are to preserve the appearance of the food, to help preserve the organoleptic properties, and to increase the shelf life of the food. In this review article, we will examine the antimicrobial activity of some natural compounds obtained from different sources and their mechanism of action.

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Plants have always been the main source of food and medicine for humans. Plant extracts have been considered in the food industry as antimicrobials, flavor enhancers, preservatives, and nutrients. Plant extracts are an excellent candidate for the replacement of synthetic compounds that have toxic and carcinogenic effects. In this study, ethanolic extract of Capparis spinosa was extracted by maceration method and the content of total phenols (by Folin Ciocalteu method), total flavonoids (by aluminum chloride colorimetry), antioxidant activity (by DPPH and ABTS free radical scavenging methods), and its antimicrobial effect (by disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration) against Enterobacter aerogenesis, Escherichia coli, Staphylococcus aureus and Listeria monocytogenes, were evaluated. The total phenols and total flavonoids of the extract were 40.28 mg GAE/g and 5.20 mg QE/g, respectively. The antioxidant activity of ethanolic extract based on inhibition of free radicals DPPH and ABTS was 52.73 and 58.62%, respectively. The antimicrobial effect of the extract was dependent on its concentration and bacterial type; increasing the concentration of the extract caused a significant increase in the diameter of the growth inhibition halo in disk diffusion agar and well diffusion agar tests. In addition, Gram-positive bacteria (S. aureus and L. monocytogenes) were more sensitive to the extract than Gram-negative strains (E. aerogenesis and E. coli). Also, S. aureus with a minimum inhibitory concentration of 4 mg/ml and a minimum bactericidal concentration of 512 mg/ml was the most sensitive species to the ethanolic extract of C. spinosa. The results of the present research show that the ethanolic extract of Capparis spinosa can be used as a natural additive in various food products.

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Pomegranate is one of the native fruits in Iran and its consumption has been following an increasing trend especially in developed countries due to its healthy bioactive compounds. In this study, effect of edible coating (Pomegranate peel extract 1% (PPE)), Chitosan Nano Particles 1%, (CSNPs), Pomegranate peel extract loaded with Chitosan and Nano Particle Size (PPE-loaded CSNPs) on ready to eat pomegranate arils during 14 days of storage under refrigerated conditions(5±1) were investigated. pH, total soluble solids (Brix), antioxidant activity, phenolic compounds, total anthocyanin, and microbial load were analyzed after 1, 7 and 14 days of storage. The trend of pH changes was the same among different treatments. However according to the results, antioxidant activity, phenolic compounds and anthocyanins were higher in the coated pomegranate arils than in the control uncoated sample. Yeasts and molds loads in coated samples and total microbial counts were lower compared with the control. Based on the results of this study, a coating of 1% nano chitosan containing 1% pomegranate peel extract can increase the shelf life of pomegranate arils at refrigerator temperature.
 

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Nowadays, with the increase in diseases and consumers’ preference for organic foods, the use of natural plant compounds to improve and increase their shelf life is on the rise. In addition, the use of medicinal plants, which can have therapeutic properties, has attracted attention. Black seed oil has attracted a lot of attention in the past due to its unique therapeutic properties. The aim of this study was to investigate the antioxidant activity and evaluate the antimicrobial activity of black seed oil against Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Staphylococcus aureus, Listeria monocytogenes and Bacillus cereus. The amount of phenolic compounds in black seed oil was measured by Folin-Ciocalteu. The antioxidant activity was determined by DPPH and ABTS radical scavenging methods. The antimicrobial effect of Nigella sativa oil was investigated according to well diffusion  agar, disk diffusion agar, interaction, minimum inhibitory concentration and minimum bactericidal concentration methods.The Nigella sativa oil had 16.25 mg GAE/g phenolic compounds. The antioxidant activity based on DPPH and ABTS radical scavenging were 86.62% and 94.85%, respectively.The Nigella sativa oil showed a significant antimicrobial effect on the tested microorganisms. In the combined mode (interaction) of Nigella sativa oil with chloramphenicol antibiotic, synergistic mode was observed for all bacterial strains. Given the significant antioxidant activity and antimicrobial effect of Nigella sativa, it can be used in food and pharmaceutical industries.
 

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The growth of fungal pathogens on the grape fruit causes a decrease in its quality and shelf life. In this study, the antifungal activity of ginger (Zingiber officinale) essential oil was investigated against fungal pathogens that cause spoilage in grape fruit. Ginger essential oil was extracted using hydrodistillation method and the content of total phenol, total flavonoid, antioxidant activity based on the inhibition of DPPH and ABTS free radicals and its antifungal activity against Aspergillus niger, Rhizopus stolonifer and Botrytis cinerea strains based on disc diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration were evaluated. The results showed that ginger essential oil has 89.80 mg GA/g total phenol and 38.60 mg QE/g total flavonoid. Its antioxidant activity against DPPH and ABTS free radicals was 73.45 and 66.53 μg/ml, respectively. The results of antifungal activity showed that A. niger and B. cinerea were the most sensitive and resistant fungal strains to essential oil, respectively, and the diameter of the inhibition zone in the disc diffusion and well diffusion agar methods, the minimum inhibitory concentration, and the minimum fungicidal concentration for the A. niger strain was equal to 13.90 mm, 14.50 mm, 8 mg/mL and 64 mg/mL, respectively. In general, ginger essential oil can be used as an antioxidant and antimicrobial agent to increase the shelf life of agricultural products.
 

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Nowadays, due to the harmful effects of chemical preservatives in food products and antibiotic resistance too, the efforts of researchers to use natural and safe antimicrobial compounds, including plant essential oils, have increased. In the present study, after collecting the Badrashboo plant from the fields around Urmia city and drying it, extracting the essential oil from the plant was carried out using a Clevenger device, and the antimicrobial effects of this essential oil against some Gram-positive and Gram-negative food-borne pathogenic bacteria were determined by methods: Disk Diffusion Agar (DDA), Well Diffusion Agar (WDA), Minimum inhibitory concentration (MIC), Minimum bactericidal concentration (MBC) and interaction with four common broad-spectrum antibiotics including Vancomycin, Erythromycin, Chloramphenicol and Gentamicin were performed. The results of the DDA and WDA tests showed that the essential oil of Badreshbo had significant antimicrobial effects on all the tested bacteria in this study. The gram-positive bacteria were more sensitive than the gram-negative bacteria in front of this essential oil. The results of the MIC test of the essential oil for Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, Shigella dysentery, Staphylococcus aureus, Bacillus cereus, and Listeria monostogenes were 2.5, 1.25, 1.25, 0.625, 0.312, 1.25 and 1.25 mg/ml. The MBC of the mentioned strains were 5, 5, 2.5, 5, 2.5, 2.5, and 2.5 mg/mL, respectively. Also, the results of the study of the interaction effect of Badreshbo essential oil with the mentioned antibiotics indicate synergistic effects of the essential oil with all four antibiotics tested. Therefore, considering the significant antimicrobial effects observed for Badrashbo essential oil in this study, it can be used in the food and pharmaceutical industries.