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  Studies have shown that camel milk and its fermented products have therapeutic properties and high nutritional value. Lactic acid bacteria play important role in Fermented dairy products. The aim of this study is to determine the lactobacillus community of camel milk. A total of 9 Lactobacillus were isolated from camel milk of Golestan province in Iran. The log₁₀ CFU of Lactobacillus per ml on MRS medium under anaerobic condition at 20, 37 and 45⁰C included 8.792± 0.14, 8.301±0.07 and 7.301±0.03 respectively. Isolates were identified on the basis of Biochemical and Phenotypic Characteristics as Lactobacillus paraplantarum, Lactobacillus ferintoshensis, Lactobacillus brevis, Lactobacillus pantheris, Lactobacillus johnsonii, Lactobacillus mali. Presence of Lactic acid bacteria was confirmed by band formation of PCR product in 1500 bp (amplification 16S rRNA gene using B27F-U1492Runiversal bacterial primer). Evaluation of their technological properties of isolates showed that isolated Lactobacillus fromcamelmilkhave lipoliticy, Proteolytic activity and high acidifying activity (except for Lb. mali and Lb. johnsonii). Also, allisolates, except Lb. Johnsonii, have autolytic activity in fair level. Based on technological properties ofisolates, Lb. paraplantarum, Lb. Brevis and Lb. pantheris are suggested as good candidates for camels milk processing or other fermentation process.  

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A total of 58 bacteria from three fermented vegetables samples were isolated. These isolates were identified as 64% Lactobacillus, 5% Pediococcus, 4.5% Leuconostoc and 26.5% unclassified bacteria based on phenotypic characterizations using morphological and biochemical tests. This identification was completed by culture-independent molecular method based on next-generation sequencing of 16S ribosomal RNA gene amplicons. The V3 and V4 regions of 16S rRNA gene were amplified and sequenced using Illumina MiSeq platform. These data were analyzed with BaseSpace software and Greengenes database. The analysis revealed 77.12% Lactobacillus, 7.51% Pediococcus, 5.61% Leuconostoc, 1.20% Acinetobacter, 1.00% Enterobacter, 0.35% Erwinia, 0.35% Dickeya as the predominant genera and 2.79% unclassified bacteria. At species level, 19.32% Lactobacillus brevis, 15.71% Lactobacillus japonicus, 13.25% Lactobacillus pentosus, 10.26% Lactobacillus senmaizukei, 4.6% Lactobacillus plantarum, 2.65% Leuconostoc mesenteroides and 2.32% Lactobacillus acidifarinae and 17.26% unclassified bacteria were identified. The same identification results were obtained by both phenotypic and Next- generation sequencing assays at genus level. In this study, application of next generation sequencing in identification of whole microbial community of this fermented product revealed that lactic acid bacteria include Lactobacillus, Pediococcus and Leuconostoc as dominant flora, were involved in fermentation process. Non-lactic acid bacteria such as Acinetobacter, Enterobacter, Erwinia and Dickeya genera also play important role in fermented pickled vegetable with tomato juice ripening. Moreover, probiotic bacteria such as Lactobacillus plantarum, Lactobacillus pentosus, Leuconostoc mesenteroides and Lactobacillus brevis were identified in this fermented product.

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Today, because of the side effects of chemical preservatives, it is suggested to use natural antimicrobial compounds such as essential oils. The antimicrobial activities of essential oils are well recognized for many years. In this study, after preparation of Artemisia absinthium essential oil, its components were identified by Gas chromatography–mass spectrometry (GC-MS). Then antibacterial activity of the essential oil was evaluated against Staphylococcus aureus, Escherichia coli, Salmonella typhi and Bacillus cereus by agar disk-diffusion, MIC and MBC methods. Based on MIC results, essential oil concentrations of 16, 32 and 64 (µl/ml) were selected to evaluate its efficacy in inactivating the growth of pathogenic bacteria on fresh lettuce. Lettuce was inoculated with Staphylococcus aureus, Escherichia coli, Salmonella typhi and Bacillus cereus and the bacterial count were enumerated at time intervals (0 h, 3 h, 24 h, and 72 h). The concentration of (Z)-β-Ocimene oxide as the major component of the essential oil was 76.53±2.36%. The results of MIC, MBC values and agar disk-diffusion showed that the most sensitive and the most resistant bacteria were Staphylococcus aureus and Escherichia, respectively. Compared to control (water), lettuce treated with 64 µl/ml essential oil at 72 h after treatment showed an up to 3.36, 2.27, 3.23 and 3.47 log CFU/g reductions in Staphylococcus aureus, Escherichia coli, Salmonella typhi and Bacillus cereus, respectively. This research showed that Artemisia absinthium essential oil may be an effective antimicrobial agent to the Control of pathogenic bacteria growth on fresh lettuce.
 

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Eve’ yogurt is one of the nutritive dairy products in Iran. The aim of this study was molecular identification of lactic acid bacteria isolated of ewe yogurts from 3 different regions of Iran (Mashhad, Dezful, and Hamedan) and assessment of their technological properties. A total of 47 isolates were molecularly identified by PCR of 16S rDNA gene and sequencing. Isolates were evaluated for technological properties including Lactic acid and diacetyl production, lipolytic, urease, and proteolytic activities. The statistical analysis of data using SPSS software indicated that diacetyl production and pH changes by bacterial isolates for 24 hours were significantly (P<0.05) different among yogurts from Dezful, Hamedan and Mashhad. The technological properties of isolates demonstrated that Streptococcus salivarius subsp. thermophilus (H1, H2) and Lactobacillus delbrueckii subsp. bulgaricus (H1, H2, H3, H7, H9, H10) of ewe’s yogurt from Hamedan have high technological properties. Also, based on the analysis results of the organoleptic properties and texture stiffness of yogurts produced by selected isolates, S. salivarius (H2) and L. delbrueckii (H3) suggested as a suitable starter culture.

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Recently, the production of fermented products has received significant attention due to health benefits. Doineh is a cereal- dairy based fermented product that is often traditionally prepared in the western regions of Iran. The aim of this study was to investigate the effect of adding 8% turnip, 8% pumpkin as a nutritious supplement and different amounts of bakery yeast 0, 0.5 and 1% to achieve an optimal formulation with a good texture and low microbial flora during 9 days fermentation.­­ The results showed that the treatments of turnip, pumpkin and bakery yeast improved the texture and reduced microbial flora of doineh. The viscosity of doineh samples containing bakery yeast increased and in contrast, the growth of pathogenic bacteria and pH significantly (p<0.05) decreased compared to the control. While, water and oil adsorption showed no significant difference (­p<0.05) in the samples. Based on the results, formulations containing 1% bakery yeast and 8% Turnip are suggested because of better texture and better control of microbial­ spoilage.
Keywords: Doineh, Turnip, Pumpkin, Bakery yeast.

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Amylase improves the texture and sensory properties of bulky bread by degrading starch and producing dextrin in order to faster metabolism by bakery yeast. This study investigates the effect of thermostable α-Amylase 0, 1.9, 2.9 (U/ml), extracted from Bacillus safensis, and fermentation time at 35, 40 and 45 minutes on the quality of bulky bread baked in oven at 210°C for 20 min.­­ The results of our study showed that adding filtered soup containing   1.9 (U/ml) and fermentation for 40 minutes  was more acceptable than other samples in terms of volume, hardness, cohesiveness and overall acceptance, but adding more amounts of amylase enzyme at ­2.9 (U/ml) level did not yield good results in terms of texture and sensory properties of bulky bread.

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The aim of this study was to isolate thermostable amylase producing bacteria from starch-rich wastewater of one of ­the canning factories and then molecular identification of these isolates. In addition, the thermostable amylase extracted from the bacterium was investigated for the optimum temperature and pH of enzyme activity. In this study, 14 heat-resistant microbial isolates were isolated from wastewater and only two isolates had amylase activity.  Molecular identification of isolates based on amplification of 16S rDNA gene by B27F and U1492R primers and then sequencing of PCR product confirmed the presence of Bacillus pumilus and Bacillus safensis. The results showed that the optimum temperature and pH of amylase activity were 60°C and 7, ­respectively, and Bacillus safensis 7.67 (U/ml) had more amylase activity than of Bacillus pumilus 6.33 (U/ml).  

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The objective of this study was to in-vitro investigation of antimicrobial activity effect of nano-ZnO loaded nanoliposomes at different level of lecithin: nano-ZnO ratio (5:1, 15:1, and 25:1 w/w) against Escherichia coli (ATCC 2592) and Staphylococcus aureus (ATCC 25923). Nano-ZnO loaded nanoliposomes were prepared through thin layer hydration sonication and heat methods. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of nano-ZnO loaded nanoliposomes and free nano-ZnO against Escherichia coli and Staphylococcus aureus were determined and their antimicrobial activities were evaluated by time- kill curve analysis. Results showed that the encapsulation of nano-ZnO in nanoliposome systems significantly increased antimicrobial activities of them by increasing their penetration into the microbial cell. Nano-ZnO loaded nanoliposomes were prepared through thin layer hydration showed higher antimicrobial activity compared to those prepared by heat method. From the time- kill curves, the log phase growth of Escherichia coli (8 hours) and Staphylococcus aureus (7 hours) in the medium containing nano-ZnO loaded nanoliposomes prepared through the thin layer hydration sonication at the highest level of lecithin: nano-ZnO ratio (25:1 w/w) at MIC and MBC values decreased to 5 and 4 hours and to 2 and less than 1 hours, respectively.
 

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In this research, in-vitro time- kill curve effect of nano-ZnO loaded nanoliposomes against Bacillus cereus (ATCC 11778) and Pseudomonas aeruginosa (ATCC 9027) were evaluated. Thin layer hydration sonication and heat methods were evaluated to preparation of nano-ZnO loaded nanoliposomes at different level of lecithin: nano-ZnO ratio (5:1, 15:1, and 25:1 w/w). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of nano-ZnO loaded nanoliposomes and free nano-ZnO against Bacillus cereus and Pseudomonas aeruginosa were determined. Results showed that the encapsulation of nano-ZnO in nanoliposome systems significantly increased their antimicrobial activities. Nano-ZnO loaded nanoliposomes were prepared at the highest ratio of lecithin: nano-ZnO ratio (25:1 w/w) showed higher antimicrobial activity compared to those prepared by heat method. From the time- kill curves, the log phase growth of Escherichia coli (8 hours) and Staphylococcus aureus (7 hours) in the medium containing nano-ZnO loaded nanoliposomes prepared through the thin layer hydration sonication at the highest level of lecithin: nano-ZnO ratio (25:1 w/w) at MIC and MBC values decreased to 3 and 3 hours and to 1 and less than 1 hours, respectively.
 

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Nowadays, the occurrence of antibiotic-resistant bacterial strains in food is increasing, which makes antibiotic treatment of infected food more difficult. One of the food sources that can cause foodborne infection is dairy products made from raw milk and one of the bacteria resistant to various antibiotics is Salmonella. The aim of this study was to investigate the presence of antibiotic-resistant Salmonella species in Poosti and Koozeh cheeses produced from raw milk in western Iran. For this purpose, the probable Salmonella species were isolated in Koozeh cheese from Bukan and Poosti cheese from Lorestan and Kermanshah. After initial phenotypic identification and biochemical testing, molecular identification was performed by amplification of the 16S rRNA gene with primers U1492R and B27F. The isolates were tested for resistance to tetracycline, oxacillin, penicillin and ampicillin. The results confirmed the presence of Salmonella enterica subspecies Typhimurium in all three cheeses among 14 Enterococcus isolates. The species of all three cheese were resistant to oxacillin, penicillin and ampicillin and the identified species of Lorestan Poosti cheese were resistant to tetracycline. But the identified species in Kermanshah Poosti cheese and Bukan Koozeh cheese were sensitive to tetracycline. The results of this study indicate that local Poosti and Koozeh cheeses in some western parts of the country may be carriers of antibiotic-resistant Salmonella strains and that in case of microbial infection caused by contaminated cheese, treatment with antibiotics may be difficult.
 

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Background: With the growing tendency of people to consume organic dairy products, there is always a risk of pathogenic microbial strains in unhygienic locally prepared products. Local sheep yogurt as an organic product is one of the most valuable dairy products in Iran.
 Objectives: The aims of this study were molecular and phenotypic identification of lactic acid bacteria (LAB) isolated from sheep yogurt from Hamadan and investigation of their pathogenic characteristics.
Materials and Methods: The LAB isolated from yogurt samples were identified phenotypically and molecularly by PCR amplification of the 16S rDNA region and subsequent sequencing. The pathogenic and safety characteristics of the isolates including antibiotic resistance, blood hemolysis, amino acid decarboxylase, DNase, and gelatinase activities were then investigated.
Results: Forty-seven bacteria were isolated from yogurt samples, and only 22 gram-positive isolates reacted negatively to catalase. Based on the results, the isolates were molecularly characterized as 4 Lactobacillus helveticus, 5 Enterococcus mori, 2 Streptococcus salivarius subsp. thermophilus, 5 Lactobacillus kalixensis, and 6 Lactobacillus delbrueckii subsp. bulgaricus. Phenotypic identification also confirmed the isolates assigned to S. thermophilus and L. bulgaricus by molecular identification.
Conclusion: The evaluation of the pathogenic characteristics of the species associated with yogurt production, S. thermophilus and L. bulgaricus, confirmed that two isolates (HL1, HL2) of L. bulgaricus are safe as starter culture for yogurt production.