Showing 9 results for Microorganism
Volume 8, Issue 30 (7-2011)
Abstract
Lycopene is a naturally red carotenoid that can be produced by some plants and microorganisms. It is not provitamin A, but it has 11 conjugated double bounds with high antioxidant activity. The antioxidant activity of lycopene has been extensively evaluated based on its ability to scavenge free radicals. Lycopene is a major carotenoids found in human serum and by virtue of its ability to interact with free radicals can preserve the important cell biomolecules such as DNA, proteins and lipids and it plays a significant role in the prevention of chronic diseases such as cardiovascular, prostate, osteoporosis and gastrointestinal. Tomato and tomato products are the most important sources of lycopene and the increasing consumption of lycopene diets is benefit to human health. Because of high demand for natural carotenoids, the production of kinds of carotenoids from microbial sources has been focused by many researchers. Lycopene has been found in several microorganisms. The production of lycopene could been enhanced by using kinds of media cultures, metabolic stimulators and inhibitors, mutagenic materials, environmental and cultural factors and genetic engineering. This review summarized the information about structure and characteristics of lycopene and it,s role in human health and introduce the some microbial resources of it.
Volume 8, Issue 32 (10-2011)
Abstract
In the recent years, interest in the use of biodegradable biopolymers for packaging applications has raised. One of the potential uses of these biopolymers is for production of active packaging containing antimicrobials. In this review manuscript, has presented some examples for applications of these packaging materials for different foods and then has mentioned the different kinds of antimicrobial agents that may be incorporated in their formulations. Many factors are involved in designing the antimicrobial packaging system. Most factors are closely related to the chemical characteristics of antimicrobial agents, the nature of the food and target microorganisms that all will be discussed in this paper.
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Volume 16, Issue 2 (6-2016)
Abstract
The composition of wastwwater in sewer lines are changing due to their nature. Wastewater contains large amount of organic materials, therfore it is suseptible to biological disintegritaion. Normally the conditions of sewers dicctate and promote the type of growth of bacteria being either aerobic or anaerobic. Previous studies have shown that large number of concrete sewer lines were found to beeffected by anaerobic bacteria activites. In this experimental investigation the aerobic biological transformation of organic matter in small diameter gravity slope wastewater collection system is evaluated. In this study a sewer network reactor at pilot scale was designed and built. The reactor consists of 15 meters length of PVC with 0.1 m diameter, two storage tanks and re circulating pump. The whole system was set up on a platform with adjustable slope. To ease the Formation of attached growth of micro organism a plastic net was attached on the inner surface of PVC pipe, thus a rough surface for attachment of microorganisms was formed. Due to the variation of hydraulic mean diameter, contact area with flowing wastewater was ranged from 1.88 to 3.77 m2 (half or full). Synthetic wastewater with characteristic municipal wastewater was used. A settled activated sludge fromYasreb wastewater treatment plant in Qaemshahr city was used to start and accelerate the biofilm growth in the reactor. In order to study bio-film attachment rate two P.V.C square plates in dimensions of 10*10 cm were placed perpendicular on the direction flow of wastewater. The reactor was conducted under aerobic conditions in a hydraulic retention time of 7 hours under constant temperature changed about 20 ±3 C. In this study parameter such as BOD, COD, TN and NH3-N and NO3-N were measured on daily basis. The thickness of biofilm increased and formed as irregular with thickness of 3-4.7 mm. Biofilm characteristics analysis showed that density and surface density were respectively 55 mg Ts/cm-3 and between 22.3 and 33.1 m-2. The concentration of suspended biomass was varied from10-15 mgl-1 at optimum COD removal. Oxygen consumption rate was estimated from decreasing rate of soluble oxygen concentration which reached to 0.21 mg l-1 min-1 after 3 weeks of operation. The highest reduction in COD and biological oxygen demand (BOD) concentration were 59% and 54% respectively . By increasing the chemichal oxygen demand (COD) loading by 70 %, removal rate of COD reduced by only 9%. Due to high COD concentration of wastewater effuluent, the nitrification process was limited. In order to nitrify the waste water, a longer hydraulic retention time(HRT) or higher recirculation is required. From the results and analysis it can seen be seen that proposed innovative method is applicable in many fields such as mountainous area, area with water stress ratio, water scarce area and ... which normally an application of conventional wastewater treatment either are costly or impractical. And also with regard to publicized incentives for using waste water reclaimation as a source of water for agricultral irrigation, thus with more precision in desigin and operation, an effluent of these new configuration of PVC pipes can be used in agri-industry
Volume 16, Issue 87 (5-2019)
Abstract
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.
Volume 20, Issue 134 (4-2023)
Abstract
The aim of study was estimated and compared intra-laboratory quantification deviation (SIR) or measurement uncertainty (MU) as a performance Charateristics in verification of the implementation step of quantitative test methods in food microbiology laboratories. The aerobic mesophilic colony counts of microorganisms (ACC) and Enterobacteriaceae colony count (ECC), as two important and common tests in the microbial evaluation of all type of food was selected and interlaboratoary standard deviation estimation of selected food items: minced meat, hamburger, soy powder, pasteurized liquid eggs, pasteurized and UHT milk, ice cream, Fruit juice, flour, cake and spice (PEPER) were calculated based on ISO-19036 standard method (2019). In this comparison, technical, matrix, distribution, confirmation and combined Uncertinity were calculated and reported. Calculation of the technical uncertainty of the ECC test in (pasteurized and ultra-heated milk, ice cream, fruit juice and pasteurized liquid eggs) by created the artificial contamination on three levels with the target organism (Shigella felxseneri) and in other food items it was natural contamination, in the ACC test was only natural contamination was calculated. The technical uncertainty results of the ECC test ranged from 0.487 to 0.07 and in the ACC test, from 0.390 to 0.105 log10 cfu/g. The highest values of technical and matrix uncertainty were observed in meat, cake, hamburger and cheese samples, which showed the heterogeneous foods (solid and semi-solid) and the lowest values were observed in liquid (homogeneous) samples. Evaluation of variability and followed the uncertainty is proposed as a way to standardize the expression of variability associated with data obtained in microbiological methods to highlight the causes and extent of several influencing factors.
Volume 20, Issue 140 (10-2023)
Abstract
Today, many different methods are applied for the correct use of foods and to prevent their deterioration. Ensuring healthy conditions for people in food consumption and consumption of healthy foods is very important for human welfare. In this study, food spoilage, the factors that cause food spoilage, its effects on a global basis, food transport systems (cold chain) and measures that prevent or delay food spoilage are discussed.
Volume 22, Issue 5 (7-2020)
Abstract
In this study, the antimicrobial effect of Coriandrum sativum L. leaves against 30 different foodborne microorganisms, including 20 bacteria, 7 fungi and, 3 yeast species, and some microbiological properties of yoghurt produced with lyophilised Coriandrum sativum L. at three different level (0.1%, 0.2% and 0.3%) and sotored at 4°C for 21 days were examined. Ethanol extract of the fresh plant extracts showed antimicrobial activity against only 9 bacteria and 1 yeast with different zone changing from 8 to 12 mm, but had no effect on fungi used in the study. On the other hand, the addition of Coriandrum sativum L. inhibited the yeast and mould growt in yoğurt samples throught the 21 days of storage. Generally, the ratio of Coriandrum sativum L. increased the number of Lactobacillus bulgaricus, but decreased the number of Streptococcus thermophilus. However it was not important statistically (p<0.05). The results indicated that Coriandrum sativum L. can be used as a good source of preventing the growt of yeast and mould which effects the storage life of yoghurt.
Volume 23, Issue 1 (1-2021)
Abstract
The use of microencapsulation technique and prebiotic compounds are among the methods used to increase the probiotics survival. This study was done to investigate the effect of combination of inulin as a prebiotic agent and inoculation of Bifidobacterium animalis subsp. lactis as a probiotic bacterium microencapsulated with sodium alginate, to produce a synthetic biochemical product with a health characteristic in cocoa cream. The study included inoculated samples that were prepared by microencapsulated B. animalis containing 2 and 3% of inulin and the control sample without it. The samples were kept at 4ºC for 6 weeks and acidity, viscosity, B.animalis survival, and sensory properties were studied on days 1, 7, 14, 21, 28, 35, and 42. It was found that in cocoa cream samples, acidity and viscosity were significantly increased and reduced, respectively, during the storage period. In samples with 2 and 3% inulin, reduced B.animalis was not significantly different, but this reduction was significantly lower than samples without inulin. After 42 days of storage at 4°C, there was no significant difference among sensory properties of samples including taste, texture, and total acceptability. The product had an appropriate physicochemical, sensory, and probiotic survival properties for industrial production.
Volume 26, Issue 1 (1-2024)
Abstract
The impact of different crop production systems was investigated on incidence of insect pests and their natural enemies, soil microflora and enzymatic activity, and quality of fruits produced in spring planted tomato at Ludhiana, Punjab, during 2017 to 2019. Production systems included conventional farming whereby indiscriminate and excessive use of agrochemicals is practiced, organic farming, and farming following Good Agricultural Practice (GAP) with IPM adoption. Higher Aphis gossypii and Helicoverpa armigera infestation was observed in organic fields followed by IPM and conventional fields. Aphid population showed a negative correlation with maximum and minimum temperature but a positive correlation with relative humidity, while the tomato fruit borer showed a positive correlation with maximum and minimum temperature but negative correlation with relative humidity and rainfall. The mean fruit yield in the farming system following IPM was maximum (50120 Kg ha-1) followed by conventional farmers’ fields (408.1 q/ha) and organic fields (403.9 q/ha). The mean spider population under organic conditions (0.39-0.56) was significantly higher than that of IPM (0.26-0.36) and conventional farmers’ fields (0.02-0.10). Soil samples from conventional fields revealed the presence of quinalphos and chlorpyriphos, while tomato fruit samples showed the presence of triazophos and mancozeb during 2017 and 2018. In 2017, the flavonoids and percent antioxidant activity in fruits from organic field were higher. The bacterial count in organic and IPM field soil increased from 5.4×107 and 4.9×107 CFU g-1 in 2017 to, respectively, 7.1×107 and 6.5×107 CFU g-1 in 2019. The activity of alkaline phosphatase and urease was highest in organic fields.
