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In this study, the antimicrobial effect of Citrus aurantium essential oil on Bacillus cereus, Listeria innocua, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and Candida albicans was evaluated. The chemical compounds, total phenol content, total flavonoids content and antioxidant potential of Citrus aurantium essential oil were determined. The results of phytochemical analysis (Ferric chloride and Shinoda) showed that, phenol, flavonoids and flavone demonstrated the presence in Citrus aurantium essential oil. Based on gas chromatography–mass spectrometry results 19 compounds identified in Citrus aurantium essential oil. Linalool (21.29 %) was the major compound in Citrus aurantium essential oil. The total phenolic content and total flavonoids content of Citrus aurantium essential oil were equal to 41.35 ± 0.46 mg GAE/g DM and 2.98 ±0.50 mg QE/g DM, respectively. The antioxidant potential based on radical Scavenging and β-carotene linoleic acid of Citrus aurantium essential oil were equal to 102.85 ± 0.60 μg/ml and 65.60% respectively. The longest and the shortest diameters of the inhibition zone at the concentration of 45 mg/ml pertained to, Listeria innocua (16.50 ±0.66 mm) and Salmonella typhi (9.80 ±0.43 mm), respectively. The minimum inhibitory concentration of the Citrus aurantium essential oil ranged from 3.125 mg/ml to 100 mg/ml, while its minimum bactericidal/fungicidal concentration ranged from 3.125 mg/ml to 200. Based on the present research, the essential oil Citrus aurantium antioxidant potential and antimicrobial activity on several food-borne pathogens tested and thus can be a good source of food industrial.

 

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Gamma Aminobutyric Acid (GABA) is a bioactive molecule with different physiological roles in the body that inhibits neuronal stimulation and inhibits the delivery of stress-containing messages, has a calming effect and is used to treat diseases. Different has an effective role. In the present study, the possibility of producing this amino acid by Lactococcus lactis NZ1330 was investigated. In order to optimize the fermentation process three levels of dairy sludge (5,10,15%), monosodium glutamate (0, 0.5 and 1%) were selected at 24, 48 and 72 hours after fermentation. The presence of GABA in the culture medium was investigated by thin layer chromatography. Spectrophotometric method was used to quantify the bands present in thin-layer chromatography. Optimization results at 95% significance level showed that the optimum treatment consisted of medium containing 11.2% dairy sludge, 0.7% monosodium glutamate and 70 hours fermentation at 32 ° C and under these conditions, GABA production was ppm. It's 400. Therefore, this combination of media can be used as a suitable substrate for the production of valuable GABA drug and bioactive compounds

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Microbial quality of raw milk is very important in two respects. First, milk consumption itself plays a very significant role in people's food tables and its high microbial load endangers consumer health. Second, if the microbial quality of milk is not suitable, from a technology point of view, milk-derived products will not have a good quality. In this project, which has been carried out in collaboration with Pegah Golestan Company, the separation process (with separators) and double bactofugation was used to reduce microbial load with the aim of reducing milk heating (in order to reduce the nutritional value as a result of heat). Milk samples used for lactic cheese production in Golestan province were examined in 2020 and 2021. After the process, total microbial counting, aerobic and anaerobic spores were counted. The results showed that by using this method, the total microbial load, aerobic and anaerobic spores of the collected milks were reduced to an acceptable level throughout the year without decreasing the microbial quality of the produced cheese during the storage period. On the other hand, the process of separation and bactofugation produces dairy sludge. Normally, dairy sludge is removed every 20 minutes, which was performed in separator and bactofuge1 to 21 minutes to reduce dairy sludge.

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L-glutamate is one of the most abundant amino acids in the body, which plays an important role in various cellular processes and also acts as a precursor of bioactive molecules, which has received much attention due to its medicinal and food applications today, and as an important amino acid. Industrial is produced commercially. L-glutamate is one of the metabolites produced by these bacteria, which is also biologically active. In this research, the production of L-glutamate by three autochthonous lactic acid bacteria (Lactobacillus brevis PML1, Lactobacillus plantarum 1058 and Lactobacillus fermentum 4-17) at three percentage levels of dairy sludge (0, 10, 20%), three levels of soybean meal (0, 2.5, 5%) and three levels of fermentation time (48, 84, 120 hr) were optimized using RSM. TLC was used for qualitative evaluation and HPLC was used for quantitative estimation of L-glutamate production, and then the antimicrobial and antioxidant properties of the fermentation extract were evaluated and compared with the control sample.
 

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Prangos ferulacea is a plant that has been used in traditional medicine for its therapeutic properties. The present study was conducted to investigate the antifungal effect of P. ferulacea aqueous extract on Alternaria alternata, Alternaria solani, Saccharomyces cerevisiae, and Fusarium solani. The antifungal methods used were disc diffusion agar, well diffusion agar, minimum inhibitory concentration (MIC), and minimum fungicidal concentration (MFC). The extract concentrations used in the study were 20, 40, 60, and 80 mg/mL. The study found that the antifungal effect was concentration-dependent and increased with concentration. S. cerevisiae was the most sensitive species to the extract while F. solani was the most resistant. At 80 mg/mL, the inhibition zones for S. cerevisiae were found to be 11.90 mm and 13.00 mm in disc diffusion agar and well diffusion agar methods, respectively. The corresponding zones were 9.60 mm and 10.20 mm for F. solani, respectively. In the combined mode (interaction) of P. ferulacea aqueous extract with nystatin antibiotic, synergistic mode was observed for all fungal strains. The MIC and MFC values for S. cerevisiae were 32 and 128 mg/mL, respectively. The MIC and MFC results for F. solani were found to 256 and > 512 mg/mL, respectively. The results of this study showed that P. ferulacea aqueous extract could be used as a natural antifungal agent to inhibit the growth of pathogenic fungi on fresh fruits and vegetables.
 

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Calotropis procera from the Apocynaceae family is called Stabregh in Iran. This plant is found in tropical areas and southern coasts in Iran and North Africa, Middle East Asia, and Southeast Asia on coastal sand dunes. In this study, the C. procera extract was separated using water solvent. The antifungal effect of C. procera aqueous extract on Alternaria alternata, Alternaria solani, Saccharomyces cerevisiae, and Fusarium solani was investigated. The antifungal activity was evaluated through, disk diffusion agar (Kirby-Bauer), well diffusion agar, minimum inhibitory concentration (MIC), and minimum fungicidal concentration (MFC). In the combined mode (interaction) of C. procera aqueous extract with nystatin antibiotic was investigated. In general, Saccharomyces cerevisiae and Alternaria solani were the most sensitive and resistant fungal strains with the highest and the lowest diameter of inhibition zone, respectively. So that the diameter of the inhibition zone for Saccharomyces cerevisiae and Alternaria solani in the presence of 80 mg/ml extract concentration was equal to 13.20 and 8.20 mm, respectively. In the interaction of C. procera aqueous extract with nystatin antibiotic, synergistic mode was observed for all fungal strains. The MIC and MFC values for S. cerevisiae were 32 and 128 mg/mL, respectively. The MIC and MFC results for Alternaria solani were found to 256 and > 512 mg/mL, respectively.
 

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Escherichia coli and Staphylococcus aureus are pathogens that have the ability to form biofilms and cause disease in food products. Due to the fact that the enterotoxins produced by these two pathogens remain in a wide range of temperature, pH and saline conditions, they cause severe infections in humans. Melittin is a natural peptide derived from bee venom that can show its antimicrobial and anti-biofilm potential through disrupting the membrane of bacterial cells. For this purpose, in this study, the antimicrobial effect of this peptide on Gram positive and negative bacteria was investigated and its minimum inhibitory concentration (MIC) was determined as 100 µg/mL and 300 µg/mL, respectively. Also, the scanning electron microscope images confirmed the antimicrobial effect of the peptide on these two bacteria. Peptide melittin caused wrinkling, deformation and creation of holes in the cell membrane of treated bacteria, compared to the control sample. On the other hand, the results of the biofilm inhibition test showed that the addition of the peptide at a concentration of 2MIC completely prevented the biofilm formation of S. aureus prevented, while this value was equal to 91.00 ± 2.82 in E. coli bacteria. Also, the increase in peptide concentration caused an increase in the destruction of adult biofilms of both bacteria. On the other hand, this peptide decreased the invasion and adhesion of these two bacteria to HT-29 and Caco-2 cells by reducing the mobility of pathogens. Therefore, according to the obtained results, melittin peptide can be a suitable alternative to chemical disinfectants that are harmful to the environment.
 

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Paenibacillus polymyxa is one of the microorganisms that has the ability to produce extracellular exopolysaccharides and antibiotics. Several factors, including culture medium content, carbon and nitrogen sources, pH, temperature, air velocity, and culture conditions, have an effect on the growth and production of higher cell mass, as well as the production of microbial metabolites. The purpose of this study was to investigate the growth rate of P. polymyxa in a culture medium containing molasses and to screen five components of the culture medium along with four factors of the fermentation conditions using the Plackett -Burman method to maximize cell mass production. The results showed that among the investigated variables, molasses brix, time, percentage of inoculation, amount of ammonium sulfate, stirring speed, and the amount of glucose and urea, as a first-order equatino, had a significant positive effect on bacterial growth and biomass production. Molasses brix medium was found to be more effective than other variables; however, pH and the amount of low-use elements had a negative effect on cell growth. The findings of this study indicated that molasses-based culture medium can be used as a cost-effective and suitable option for the growth of P. polymyxa.