جستجوی مقالات مرتبط با کلیدواژه « Microbial load » در نشریات گروه « کشاورزی »

Grape is a major horticultural crop with a high nutritional value in the world. The optimal geographic and climatic conditions in Iran have positioned it as one of the most important regions for grape cultivation in the world. Black rot, caused by Aspergillus niger, is a highly destructive fungal disease that affects the grapes by targeting wounded areas. It causes crushing of the grapes, the falling of berries, and reduces transportation and storage properties (Ponsone et al., 2011). Various methods, such as fumigating bunches with sulfur dioxide and storing them in a modified atmosphere, have been used to control fungal rot and prolong the shelf life of grapes. However, each method has its limitations. Grape fumigation with sulfur gas is harmful to human health (Duarte-Sierra et al., 2016) and the efficiency of modified atmospheric storage on rot control and maintaining the quality of grapes depends on the type of variety, storage temperature, and especially gas concentration (Himelrick, 2003).Given the lack of efficiency in traditional methods, it is imperative to introduce modern techniques that can effectively disinfect microorganisms. These advanced methods offer several advantages, including the preservation of crop quality, an increase in crop shelf life, the promotion of good health, and substantial economic benefits. A technique of this type includes using non-thermal (cold) plasma (NTP) technology to eliminate food microorganisms (Bourke et al., 2018). The effect of cold plasma at atmospheric pressure on the reduction of bacterial populations in food products such as lettuce, tomato, strawberry, and cherry tomato has been reported (Bermúdez-Aguirre et al., 2013; Pasquali et al., 2016; Ziuzina et al., 2014). Research has shown that cold plasma can effectively inactivate Aspergillus in various orchard and agricultural products (Butscher et al., 2016; Ghorashi et al., 2020; Selcuk et al., 2008). The effect of cold plasma on the quality characteristics of the product during the post-harvest period has also been investigated. Blueberries treated with cold plasma for less than 15 minutes showed remarkable results after 10 days, the fruit exhibited reduced lipid peroxidation and darkening, with no impact on the total anthocyanin content, pH, or firmness of the product (Hu et al., 2021). In a study by Rana et al. (2020), it was found that subjecting strawberries to 15 minutes of cold plasma with packaging after 5 days of storage at 25°C had no significant impact on pH, TSS, and moisture content of the fruit.The review of the literature reveals the absence of research on fungal disease control and grape quality evaluation following the use of NTP. This study aims to investigate the efficiency of plasma treatment in reducing the infection with Aspergillus fungi, along with examining the physical, chemical, and mechanical properties of Fakhri grape.

This research was conducted as a completely randomized design in a factorial experiment at four plasma levels (0, 10, 20, and 40 s) and five storage periods (1, 2, 3, 4, and 5 weeks) with three replications at 4°C.  A plasma generator was first designed and manufactured in this study. A specifically designed and fabricated plasma application probe was also developed for grape berries. The individual grape berries were then sterilized with 1% sodium hypochlorite under a laminar hood for 2 minutes. Afterward, they were rinsed three times with sterile distilled water to remove any remaining disinfectant residue from their surfaces. Sterilized berries were immersed in Aspergillus spore suspension with 105 spores.ml-1 concentration. Finally, all samples were dried on paper filters and prepared for different plasma treatment durations (0, 10, 20, and 40 s). The treated samples were stored at 4°C, and the infection percentage and microbial load were measured on a weekly basis. To assess the preservation quality, chemical parameters such as pH, TSS, and TA, physical parameters (color change and weight loss), and mechanical properties were measured every week. Additionally, thermal imaging was performed weekly.

Plasma application during storage significantly reduced the infection percentage and microbial load in Aspergillus-inoculated samples. At the end of the storage period, the infection percentage and microbial load in the 40-second plasma treatment were 5% and 2.5 CFU g-1 respectively, while in the control group, the infection percentage was 100% and the microbial load was 4 CFU g-1. At the end of the storage period, the lowest pH level in the plasma was observed for 40 s plasma. This could be attributed to effective contamination control, as fungal contamination leads to alkalization of the environment. The highest amount of TSS was also observed in control and 40 s plasma. But in the 10 and 20 s plasma treatment, the process of changes was gradual and not significant. The higher TSS level of control and 40 s plasma can be due to the weight loss caused by the spread of contamination and moisture leakage caused by damage to the tissue. This decrease in moisture leads to an apparent increase in the TSS index. Research has shown that plasma primarily affects the surface characteristics of products, and when applied with the appropriate voltage and duration, it does not alter the internal chemical properties (Hu et al., 2021). Over time, weight loss increased in all treatments. This increasing trend during the storage period is higher in control and 40 s plasma compared to 10 and 20 s plasma. Therefore, the weight loss in the control can be due to the spread of contamination and aging of the product over time. However, the weight loss in the 40-second plasma treatment can be due to the destruction of the fruit tissue caused by longer duration of the plasma application.In the current research, by increasing the duration of plasma application to 40 s, a significant decrease in L*, a*, and b* indices and an overall change in the color of the product was observed. Research shows that in blueberries, inappropriate duration of plasma treatment causes the loss of wax on the fruit surface and leads to darkening of the product (Hu et al., 2021). The highest and lowest changes in temperature drop were observed in the control treatment (5°C) and 10 and 20 s plasma (3 and 3.5°C, respectively). According to research, an increase in fungal contamination leads to a decrease in humidity, increases weight loss, and subsequently a decrease in product temperature. A decline in mechanical characteristics was noted for the control and plasma treated samples during the storage period. The lowest value for indicators was observed in the 40 s plasma treatment. However, no significant difference was observed in samples treated with plasma for less than 20 seconds compared to the control group up to the middle of the storage period. According to a report by Misra et al. (2014), plasma application can reduce tissue softness. Therefore, optimizing its plasma duration and intensity is very important (Pan et al., 2021).

Our experiments aimed to investigate the effect of NTP treatment on controlling Aspergillus infections while preserving the quality properties of Fakhri grapes. The obtained results are important for two main reasons. Firstly, an innovative probe was designed for plasma applications, specifically tailored to the shape and size of individual grapes in order to thoroughly cover them with plasma. Secondly, application of plasma was carried out for the first time and yielded valuable results, indicating that this technique can control fungal infections and preserve the chemical, physical, and mechanical properties of grapes.

Microbial contamination of date fruit, as one of the important and strategic agricultural products of Iran, is one of the important causes of waste of this product. Therefore, in this research, the effect of cold plasma as one of the new technologies for maintaining the quality and durability of Mazafati date using a sliding rotary arc discharge device, in two treatments of plasma application time in 5 levels (30, 60, 120, 180, and 240 s), with the aim of achieving the optimal time and different gases at 3 levels (air, argon and oxygen), with the aim of determining the best type of gas, was investigated. Microbial load evaluation by microbial counting method on 0, 3, 6 and 9 days after plasma treatment were performed. Sensory evaluation of date samples was performed after 9 days of plasma treatment by 5-point hedonic method. The results of microbial analysis showed a reduction of 0.48 logarithmic cycles of aerobic mesophilic bacteria in air-plasma samples and also a reduction of 0.35 logarithmic cycles of aerobic mesophilic bacteria in oxygen-plasma samples compared to the control sample. The lowest mean growth of aerobic mesophilic bacteria was observed in the sample with plasma treated time of 240 s. Plasma treatment with arc discharge device significantly reduced the microbial load, so air and oxygen with duration of plasma treatment of 240 s had the highest effect in reducing the total count of aerobic mesophilic bacteria. Also, storage time had a significant effect on microbial load and the total number of aerobic mesophilic bacteria on the last day of storage was significantly (p <0.05) higher than other days. Sensory evaluation also showed a significant difference between the sensory characteristics of plasma-treated samples and the control sample. Based on the scores of the evaluators, plasma-treated samples with air in the characteristics of flavor, texture, color and overall acceptance had 59, 45, 8 and 39% more scores than the control sample, respectively, which indicates the effectiveness of the plasma-treatment method in maintaining the quality of Mazafati dates.

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.

The foam mat drying is a process in which liquid food is converted into stable foam by combining gas into it, and then dried at a relatively low temperature. In current research, shrimp foam was prepared using 0.25% Cress seed gum and dilution with ratio of 1 shrimp to 4 water after 4 min whipping and then foam with 4mm thickness dried in a drier with 70°C. Shelf life of powders for 6 months and two storage temperatures (ambient and refrigerate) were measured. The experiments included density, water activity, water absorption, oil absorption, total volatile base nitrogen (TVB-N), thiobarbituric acid, peroxide and microbial count including coliform bacteria, mold and yeast, and total count. The count of mesophilic, psychrotroph, total coliforms, vibrios, mold and yeast was increasing during shelf-life time. On the other hand, fecal coliform and escherichia coli and Salmonella were not found in shrimp powder samples during shelf-life period. During the shelf-life period of water absorption, oil absorption, water activity, decreasing trend and TVB-N, thiobarbituric acid, peroxide and density were increasing. In refrigerated samples at the end of the 6-month period, there was a lower level of TVB-N, thiobarbituric acid, peroxide and water activity than those stored in the ambient temperature.

To avoid or postpone the spoilage of meat goods and their products, various chemical, physical and microbial methods such as the incorporation of antioxidants, using suitable antibacterial substances have been suggested. In this analysis, three ranges of essence concentrations (0.25, 1.125, and 2 percent) and three storage courses (1, 6, and 11 days) were used to analyze the impact of applying essence Stachys schtschegleevii  to ground Minced calf meat at refrigerated temperature. The capacity to inhibit DPPH free radicals, regenerative power, meat myoglobin amount, peroxide number, pH, and microbial load of the samples were examined by gas chromatography fitted with mass spectrometers after recognizing chemical compounds. Additionally, Statistical analysis plus process optimization were also carried out by response surface method. The findings of this analysis revealed that Sesquiterpene (24.35 percent) was the highest composition of the essence. Based on the acquired results from the optimization Process it seems that the samples containing 1.24 percent of Stachys schtschegleevii essence with 2 days of storage were the most suitable manner (0.824). With having an insightful view of the obtained results of the experiment, it could be indicated that the nature of this plant can greatly minimize the spoilage of minced calf meat.

there is a growing request for healthy fresh-cut products globally. However, due to the higher respiration of this kind of products and their suseptability to bacterial and fungal pathogenes, they spoil immediately after processing. These microbial activities usually cause a decrease in the quality and marketability of the product, including changes in its aroma, taste and appearance. The fresh-cut fruit and vegetable industry is one of the relatively new sectors and while the industry is growing, it is producing new products. Tissue rupture and cell rupture in these products leads to a decrease in their shelf life. On the other hand, these products need serious attention due to increased enzymatic activity, respiratory factors and microbiological considerations.In recent years, there has been growing evidence of consumption of minimally processed fruits and vegetable for the prevention of many chronic diseases. Some chemicals like chlorine, calcium chloride, etc., are used for sanitization purpose in fruit and vegetable industry, but these chemicals form carcinogenic chlorinated compounds, which have adverse human health impacts. Therefore, advanced alternative sanitization techniques, processing methods and improved packaging materials may be implemented for ensuring safety and extending the shelf life of fresh-cut fruit and vegetables. Application of edible coatings showed acceptable results on microbial load reduction and better preservation of processed products from the fruit to vegetables. Apple with proper nutritional value as a healthy snack have been considered in the diet of schools, public consumption and families. Finding a safe treatment to increase shelf life of freshly cut apples without harmful effets on environment and consumer is the main goal to this reaserch.   In this study, the effect of fennel essential oil (Foeniculum vulgare L.) with Aloe vera gel (in 3 levels of zero, 10 and 25 ml / l) and two magnetic field intensity (0 and 60 ml Tesla) in 3 replications during 7 days and in two storage  temperatures (8 and 25 ° C) were observed. All treatments except the control were coated with Aloe vera gel. It was done in factorial format with a completely randomized design. In which traits such as color quality, SSC, pH, physiological weight loss, and browning rate were studied.   Discussion and The results showed that the presence of the magnetic field in all samples treated with Aloe vera gel reduced the degradation, decrease oxidation and increase preservation of the appearance indices of apple slices. The presence of Aloe vera gel in all cases reduced water content reduction and weight loss. In the samples treated with different levels of fennel essential oil, fungal and bacterial growth was prevented, but in terms of appearance indices, it had a great decrease in quality and increased browning. No mold and fungal growth was observed in the samples at 8 and 25 ° C. Apparently, apples treated with 25 ml of essential oil lost their marketability. The use of Aloe vera treatment alone and without essential oil with a 60 ml Tesla magnetic field was found to be the best treatment. In general according to the results of this study, the application of fennel essential oil, which has antioxidant properties in lower concentrations, is useful to prevent the prevent fungal and bacterial growth, but is not suitable in terms of maintaining the appearance and reducing tissue destruction and causes faster and higher oxidation. Apple slices treated with high essential oil concentration became completely brown and lost their marketability even more than the control samples. Finally, it could be said that Aloe vera gel treatments in which a magnetic field was applied, in addition to water retention, had the best appearance and less oxidation. However, the use of Aloe vera gel and magnetic field to maintain the appearance is very useful and can be used in this industry.

Nut's seeds can be a source of contamination with various types of microorganisms and so some of them are important for public health.  Therefore, with regard to household consumption of those type of seeds and their application in food industries, and also due to the fact that some of them are imported from other countries so they may have the possibility of microbial contamination from the source, therefore the purpose of this study was to evaluate the efficacy of UV irradiation in reducing the microbial load of some consumed seed nuts. Six types of beans including sunflower seeds, watermelon, pumpkin, walnut, pistachio, and hazelnut were randomly sampled in bulk from Tehran retail market. Testimonials were tested by methods in the Iranian national standard and food and drug organization standards. Subsequently, infected seeds were irradiated in 1, 2 and 3 layers of thickness and time at 5, 10 and 15 minutes in a UV cabinet with a wavelength of 254 nm and subjected to appropriate microbial tests. According to the results, the irradiation time and thickness were significantly affected by the total microbial count of pistachio, walnut and hazelnut (p<0.01). Also,  it has a significant effect on the coliform count  of pistachio, walnut, hazelnut seeds, pumpkin seeds, sunflower and watermelon, and the mould count of pistachio, walnuts and hazelnuts, sunflower seeds and a watermelon (p<0.01). It had less significant effect on the number of molds in pumpkin seeds (0.01<p).

Milk is the most consumable dairy product in the world which is predominantly treated to heat pasteurization and sterilization processes to increase safety and shelf life (Meshref 2008). Heat treatment can cause undesirable protein denaturation, non-enzymatic browning, loss of vitamins and volatile flavor compounds, freezing point depression, and flavour changes. Due to using high temperature of heat in this process, the nutritional composition and sensory properties of milk are changed (Herceg et al., 2012). Today, there is interest in use of high-intensity ultrasound waves with a mild heat treatment process to deactivate microbes and enzymes leading to spoilage and degradation of safety in foods. The aim of this study was to evaluate the effect of ultrasound process as an alternative for high temperature heat process on microbial count, lipid oxidation as qualitative parameter and vitamins as nutritional characteristics of milk.

Fresh milk was prepared from the Firoozkandeh cow farm (Sari-Mazandaran-Iran) and transferred to the laboratory in cold conditions then it was treated by ultrasonication techniques at 3 temperature levels of 45, 55 and 65 ° C and duration 5, 10 and 15 min using ultrasound probe type (350 W) in two intensities of 50 and 75% and ultrasound bath (280 W). The control sample was heated at 90 ° C for 10 min. Total viable count of bacteria, total count of mold and yeast, count of coliforms, psychrophilic bacteria and Escherichia coli in raw milk, control milk and treated milk with ultrasound were measured. Plates with 30 to 300 colonies were selected to count of colonies and microbial changes of milk samples were reported based on Log CFU/ml. The effect of thermo sonication on the lipid oxidation of milk was evaluated by measuring peroxide value and thiobarbituric acid value. Riboflavin and thiamine as water-soluble vitamins and retinol and tocopherol were measured as lipid-soluble vitamins by HPLC method.

It was found that an increase in ultrasonication temperature from 45 to 65°C and duration from 5 to 15 min, increased lipid oxidation of milk and the samples treated with ultrasound bath had the least amount of peroxide value (0.019±0.01 meq O2/Kg oil) and thiobarbituric acid value (0.03±0.0 µg/Kg). Raw milk has the least oxidation because no heat process was applied to it. The presence of air bubbles during sonication and solid particles of milk leads to the formation of nuclei for free radicals and intensifies the oxidation process. The formation of primary and secondary compounds resulting from fat oxidation depends on the variables of ultrasound treatment, the time and temperature of treatment with ultrasound, as well as the type and intensity of ultrasound. When sound waves pass through a liquid; in each section of the fluid, a continuous compression occurs and an exponential cycle occurs. Because of the sound energy cannot be absorbed by molecules, the fluid is drawn to one side and the cavitation phenomenon occurs, which is associated with the formation of small gas bubbles. The collision of gas bubbles encounters the formation of other waves. Given that the effects of ultrasound depend on the number and severity of explosive bubbles inside the liquid over time and type of treatment environment. In same sonication condition the effect of increasing in temperature on vitamin degradation was higher than that of ultrasound type, and the highest levels of thiamin (10.80±0.06 µg/100g), riboflavin (97.55±0.68mg/100g) and retinol (14.9±0.09µg/100g) degradation occurred in the control sample. The effect of temperature on riboflavin and thiamine amount was significant (P<0.05) and with increasing in temperature riboflavin and thiamine amount decreased and there was a significant difference (P<0.05). The ultrasound process was effective in reducing riboflavin and thiamine amount, resulting in a decrease in their amount, and the probe type of ultrasound caused the most vitamin degradation. The separate and interaction effects of each factor were not significant on retinol content. The retinol content decreased with increasing in temperature but the difference was not statistically significant. The reason for the decrease in tocopherol during sonication treatment can be attributed to the anti-radical properties of vitamin E. Also, the effect of ultrasound on water-soluble vitamins and lipid-soluble soluble vitamins showed lower levels of degradation of these vitamins compared with conventional heat-treated specimens. Very few studies have investigated the direct and indirect effects of ultrasound on the nutritional value of food, and the use of ultrasound at low temperatures reduces the probability of nutrient degradation. Increasing in time of ultrasound was effective in reducing the count of microorganisms but it had a statistically significant effect (P<0.05) on reducing the number of Escherichia coli, mold and yeast. Ultrasound type and ultrasound temperature had a significant effect on the total viable count of bacteria, coliforms, mold and yeast and psychrophilic bacteria (P<0.05). Probe type ultrasound is very suitable for the 75% oscillation range in the destruction of a variety of microorganisms, but increases the fat oxidation. The effect of none of the studied variables on count of Escherichia coli was statistically significant (P<0.05). When probe type of ultrasound used, the antimicrobial effect of sonication increased with increasing in intensity of ultrasound due to the cavitation effect. Increasing the time of ultrasound process has reduced the number of bacteria and in this regard, probe ultrasound has been more effective than ultrasound bath, which is consistent with the results of the present study. In addition to the cavitation phenomenon, ultrasound application results in a change in permeability of the membrane. Entering high amounts of water into the microbial cells can easily damage the cells.

The results showed that ultrasound has been able to reduce the microbial load of milk and it made fewer changes in vitamins than milk treated with conventional method. In this regard, the ultrasound probe has been more effective at 75% intensity. The use of ultrasound probe type at 55 ° C and 75% intensity for 10 minutes is recommended as a non-destructive process for milk pasteurization.

Cold plasma is a dry, non-thermal technology with no chemicals capable of working continuously at atmospheric pressur. In the present study, plasma discharge of atmospheric pressure dielectric barrier with gases (air, nitrogen, and argon) was applied to the plasma for (0,5,15,25) min at the surface of curcuma longa samples to reduce total microbial, coliform, yeast and mold, Clostridium perfringens was performed. Results of microbial tests showed that irradiation of plasma with nitrogen gas for 15 minutes reduced curcuma longa microbial load with minimal effect on physicochemical properties.Control samples lacked coliform and Clostridium perfringens. The results of physicochemical properties of the samples (color and antioxidant activity) showed that the effect of gas type on any of the curcuma longa color indices was not significant, while with increasing plasma duration the mean of all three color indices decreased, which decreased in There were significant differences between 15 and 25 minutes.(p<0.05). nvestigation of the effect of gas type and duration of plasma application on the inhibitory index of curcuma longa samples showed that the type of gas used had no effect on this index(p>0.05), while the effect of time was significant for this index and their antioxidant properties compared to the control sample Decreased(p<0.05). The results of sensory characteristics (color, odor, appearance and taste) of the samples showed that the type of gas used did not differ significantly on the sensory parameters of the samples, while with increasing plasma duration the mean values ( Except for the taste index of the samples which decreased significantly between 15 and 25 minutes(p<0.05). In general, cold plasma is a novel method of food processing that, given its non-thermal nature, can be a good alternative to other methods used for food sterilization and pasteurization.

Herbs are natural substances with antioxidant properties that are effective preservatives in raw and unprocessed food which are susceptible to contamination by bacteria( vegetative and spore forms), yeasts and mold.at this study , treatment of spices ,cinnamon, ginger and cloves was carried out with ozone gas at a concentration of 4 g/hr in 0,10,20,40,60 minutes and chemical and microbial properties were evaluated. The results showed that the type of spices and treatment time and the interaction of two factors had a significant impact (P

Today, tendency to use drugs and therapies with herbal and natural products are increasing because negative effects of chemical drugs and environmental pollution have been proved. Collection and handling of medicinal plants are not usually done in sanitary conditions and difference in cultivation conditions can also increase pollution, influencing the maintenance period and damaging the aspect and the potential benefit of medicinal plants. Medicinal plants decontaminate with different methods that each of these methods has different effects on their microbial load. Therefore it seems essential to use of methods that can have the highest effect on microbial load decrease and the lowest effect on active substance of these plants.
In order to evaluate the effects of Ozone gas and gamma irradiation on microbial load of Melissa officinalis, an experiment was conducted based on randomized complete block design with three replications. Plant samples were collected from the Research farm of, Ferdowsi University of Mashhad. Meliss leaves were treated by Ozone gas concentrations 0.3, 0.6 and 0.9 ml/L for 10 and 30 min and irradiated at dosages 3, 7, 10 and 15 KGy by a Co60 source. Then microbial load of Meliss leaves were measured. Coliform bacteria were determined using Violet Red Bile lactose (VRBL) agar (Liofilchem Co., Italia), according to the method of ISO4832. According to ISO 7954, yeast extract of glucose chloramphenicol agar (Liofilchem Co., Italia) was used for determination of mold and yeast. The total count (plate count agar, Liofilchem Co., Italia) was determined by method of ISO 4833, that each replicate was tested with duplicate pour plates. Ozone gas was produced by corona discharge Ozone generator with production capacity 10 g/h of Ozone gas (OZONEAB co. A.S10. Iran). Analysis of variance and means comparison were calculated using SAS 9.1 (Cary, NC, USA, 2002-2003). Means square comparisons were different at the 5% significance level by the least significant difference test.
The effect of Gamma radiation on microbial load such as total count, molds, yeasts and Coliform was significant (p

Use of sewage sludge as a cheap and nutrients-rich fertilizer has been common in some regions of Iran. But, using sewage sludge in large quantities can lead to accumulation of heavy metals in plant. The goal of this study was to evaluate the effects of sewage sludge on heavy metals concentrations in plants and some morphological characteristics of lettuce. This research was conducted in greenhouse of Faculty of Agriculture at Lorestan University. Treatments included five levels of sewage sludge: control (no sludge), 25, 50, 75 and 100 tons per hectare (t/ha), with four replications based on a completely randomized blocks design. Plant tissue analysis showed that sludge application significantly increased concentrations of Fe, Cu, Cd and Pb in lettuce shoot, root, and stalk. In 100 t/ha treatment, the highest concentrations of Fe (6.16 mg.kg-1) was in shoots and the highest concentrations of Cu and Pb, (1.49 and 1.20 mg.kg-1, respectively) was observed in the root and highest concentrations of Cd (0.43 mg.kg-1) was found in lettuce stalk. The results showed that application of sewage sludge significantly increased dry weight of biomass and root, plants height, root length, and leaf area index of lettuce, but had no significant effect on chlorophyll content. The highest amounts of these growth parameters were obtained in the treatment of 100 t/ha. Thus, because of concentration of heavy metals in sewage sludge, its long term application poses risk of heavy metal contamination in the soil and, consequently, health risk to the human and animal food chain. Therefore, according to the research results, it is recommended that sewage sludge should not be used for growing edible food crops. Indeed, before using sewage sludge in different farms, it is necessary to be examined for microbial load and suitable recommendations should be made based on local conditions, vegetation type, and soil characteristics.

In order to reduce microbial load in edible and medicinal plant products, gamma irradiation is used. On the other hand, there is the risk of structural changes in the composition of chemical compound due to gamma irradiation. The purpose of this study was to evaluate the effect of gamma irradiation on the physicochemical, microbial properties, and antioxidant activity of dry red grape marc. Samples of dry black grape marc were exposed to gamma irradiation at doses of 0, 10 and 25 kGy. Microbial load, pH, color, DPPH radical scavenging and total phenolic content of treated samples were measured and compared with control (Non- irradiated sample). The results showed that exposure to a dose of 25 kGy did not have a significant effect on pH (p

Saffron is considered as a valuable produce by producers and traders. Unfortunately, the use of its floral by products like petal which have proven to be antioxidant, antimicrobial and nutritional value is limited. In order to investigate the application of saffron petal extracts as an ameliorative on postharvest and processing quality of fresh-cut ‘Crimson Sweet’ watermelon, a completely randomized designed investigation was done on watermelon cubes with 1cm diameter (1±0.5 gram mean weight). Prepared watermelon cubes were divided into four groups and treated with saffron petal extract (10 % V/V) for 10 minutes, UV irradiation (maximum wavelength 253.4 nm and 15W) for 5 minutes, 10 minutes of saffron petal extract then UV irradiation for 5 minutes and control. After the application of treatments, fresh-cut watermelon cubes were stored at 5±0.5 ºC for 14 days. Sampling and observation of the studied characteristics (physiological loss in weight, soluble solid content, lycopene, microbial load and color quality (Chroma Hue)) was done every two days to find the trend of changes during the retention period. The results of experiment showed that petal extract of saffron could not decrease weight loss but it was significantly effective in lowering microbial load and increasing color quality, and prevention of lycopene degradation (P≤5%). Although treatment of UV䣱 had better efficiency to suppress microbial load significantly (P≤5%).

“Ready to eat” pomegranate arils in addition to unique sensory and nutritional properties, provides the possibility of increasing the pomegranate consumption. The pomegranate fruit is native to Iran, so it is important pay attention to the pomegranate processing industry. The present study investigated the effect of modified atmosphere packaging and vacuum packaging on some quality properties of pomegranate arils with response surface methodology. The extracted pomegranate arils packed with three gas concentrations of oxygen includes vacuum packaging (%0), modified atmosphere (%10) and normal atmosphere packaging (%21) and kept them in storage temperatures (4, 12 and 20˚C ( for 16 days. Measurement of total soluble solids, titratable acidity, total anthocyanin, antioxidant activity and microbial load was performed on samples in intervals of 4,10 and 16 days after packaging. Antioxidant activity decreased with storage temperature and time increasing that had direct relation with anthocyanin decreasing during storage period. The highest of total anthocyanin content and soluble solids was in modified atmosphere packaging. Also, antioxidant activity by acidity increasing in normal atmosphere packaging (control) showed a significant increase. Microbial quality is an important parameter in determining the shelf life of foods. The lowest and highest of microbial load was, respectively, in vaccum and normal atmosphere packaging (control) that titratable acidity increasing and soluble solids decreasing was due to microbial activity increasing in normal atmosphere packaging. After final optimization, the best of gas oxygen concentration, storage temperature and time for maintaining of pomegranate arils was, respectively, %7, 5°C and 11days. At the optimal point, acidity, maximum total soluble solids, maximum antioxidant activity and total anthocyanin content, minimum total count and yeastmold was determined 1.13 (gr/100ml), 17.6 (°Brix), %56.7, 224 (mgL-1), 2.98 Log cfu/g and 2.95 Log cfu/g respectively.

Fresh-cut produce graduated to retail during the1990s, especially for lettuce, cabbage, carrots and other similar vegetables. The high microbial loads of these products after harvest can be substantially reduced through a cleaning in flowing chlorinated water and adistribution under ensured controlledrefrigeration. Therefore, a good number of convenient ready-to-use greens were launched to the market in the past decade. Nowadays, theuse of this technology to achieve similar results in fruit products is one of the most challengingtargets for processors. However, there is anumber of issues that still need to beovercomebeforefresh-cut fruit commodities can be sparked off to anoutstanding position in the segment of lightly-treatedrefrigerated foods. The importance of freshly cut products increases day by day. Tissue and cell rupture leads to a decrease in the shelf life of these products. On the other hand, these products due to increased enzyme activity, respiration rate and microbiological considerations that affect the health of these productsrequires highly attention.To increase the shelf life of the products and prevent undesirable changes in cut slices of fruit or vegetables a coating on the surface of these products has been suggested. Mucilages and essential oils of herbs are natural compounds that can be used to create such covers. The advantages of these coatings are their bactericidal effect, maintenanceof pleasant taste and other physical and chemical characteristics of the product and even decrease of environmental pollution. In this research, the effect of natural compounds such as Zataria multiflora essential oil (EO) and Plantagopsyllium mucilage on storage life and microbial load of fresh cut carrot was studied.
The research was conducted in two separate experiments on fresh-cut carrot: In the first experiment, the effect of different concentrations of Plantago psyllium mucilage (0,100, 200, and 400mgL-1) and four concentrations of Zataria multiflora essential oil (0,100, 250,and 500 mgL-1), in a factorial experiment on the basis of completely randomized designwith16treatments and three replications was evaluated. In the second experiment application of essential oil and mucilage on microbial load of fresh-cut carrot was examined in a split plot experiment on the basis of randomized complete blocks design with six treatments and three replications which Zataria multiflora EO (500 mgL-1) and Plantago psyllium mucilage (400 mgL-1) was set as main plot and storage time was set as subplot. The serial dilution technique and cultivation in special culture media were used to determine the microbial load. Treated samples were then packaged in polyethylene trays (175mL) and were stored at 4°C. After10 days of treatment different parameters such as weight loss, total soluble solids (TSS), titratable acidity (TA), pH, color, organoleptic properties, the amount of skin whitening and microbial load were evaluated.Means were compared using LSD test at the significant 5% probability level.
The results showed that the treatments had a significant effect on weight loss. Essential oil and mucilage treated samples with different concentrations and also a combination of the two had less weight loss than the control. Different concentrations of essential oil and mucilage individually significantly affected titra table acidity, soluble solids and pH. Samples treated with 100 and 250 mgL-1essential oil, and with 100 and 200 mgL-1 mucilage had the highest acidity, and showed significant increase compared to the control. A little color changes occurred in the treated samples and their colors were very close to the control. Combination treatment with 100 mg.L-1essentialoil plus 100 mgL-1mucilagesignificantlyreduced skin whitening of fresh cut carrot. Analysis of variance indicates significant effect of treatments on all microbial contaminations which were evaluated. The means of aerobic mesophilic bacterial contamination and the coliform bacterial contamination were 6.67 log CFU/g and6.37 log CFU/g, respectively. Only mold and yeast contamination significantly increased during storage and was more pronounced in samples treated with psylliummucilage. After 10 days of storage, although some bacterial contamination increased, this increase was not significant. Fungal contamination starts at 5.35 log CFU/g and endsat 6.64 log CFU/g, which is approximately 1.3 log CFU/g increased. E. coli contamination was not observed in samples.According to the standards threshold, in this experiment, aerobic mesophilic bacteria contamination of the samples (except for samples coated with mucilage after 10 days of storage which their contamination exceeded) was in the standard threshold.However, coliform bacteria, mold and yeast contamination in all samples exceeded.
In general, results of this study showed that application of natural compounds of medicinal plants as edible coatings improved the quality and -extend the shelf life of fresh cut carrot. .However, disinfection of the product in this experiment was not sufficient to reduce the microbial contamination properly and treatments used could not reduce it at the standard limits, appropriate disinfection methods such as radiation and higher concentrations are also investigated in order to export this recommended product

The utilization of organic fertilizer is an effective method in organic culture of medicinal plants. The aim of this study was to determine the effect of organic manure and compost application on growth، development، essential oil content، and microbial load in valerian. The experiment was conducted in randomized complete block design with 3 treatments and 3 replications. The treatments applied organic manure and urban compost compared with control. Morphological traits and essential oil content were recorded and compared in each treatment، and root samples were analyzed for mesophilic aerobic bacteria، total coliforms، yeasts and moulds، and E. coli according to the standard guideline. Results showed that the application of organic manure increased plant leaf area، plant height، and essential oil content significantly (p <0. 05); whereas the application of compost could increase plant leaf area، fresh and dry plant weight، fresh and dry root weight، plant height، and essential oil content. Both fertilizers specially compost decreased root length significantly. The effect of treatments on essential oil content was also significant (p <0. 05)، both organic manure and compost could increase it in comparison to control. Results of microbial load analysis indicated that the effect of treatments on all microbial contamination was not significant; E. coli existence was not proved in any of، treatments and in other microbial contamination all treatments were in the same level. According to these results، the organic manure and compost application could increase essential oil content، and compost increased underground parts of plant weight more، thus increasing the essential oil yield. In microbial quality، organic manure and compost application did not increase product contamination significantly compare to control. So the application of this kind of fertilizers can be advisable in valerian culture.

Gamma irradiation can be used to increase post harvest quality of medicinal plants by decreasing microbial load and decontamination. Microbiological changes associated with food irradiation include the reduction or elimination of spoilage and pathogenic microorganisms, insect disinfestation and parasite disinfection. This factorial experiment was conducted on the basis of randomized complete block design with three replications. The effects of gamma irradiation on decreasing the microbial load of some medicinal plants including (Mentha piperita), lemon balm (Melissa officinalis), Summer savory (Satureja hortensis) and (Zataria multiflora) were investigated. Leaves of Lemon Balm, summer savory, pepper minit and thyme were irradiated at dosages of 3, 7, 10 and 15 KGy by a Co60 source, then total count, total Coliform and mold and yeast of the samples were studied. Gamma irradiation decreased microbial load of medicinal plant samples. The microbial load was detected in samples treated with 15 KGy radiation and control. Also, the result showed the highest and the lowest microbial load in peppermint and Iranian thyme, respectively. Results of this study show that gamma irradiation can be used as an important decontamination method to reduce the microbial load of medicinal plants.