Days In Tomato Research Articles

Graphene fortified polyvinyl alcohol based nanofibre membranes for preserving perishable food

In recent years, graphene as a biomaterial has received considerable attention due to its outstanding physio-mechanical properties. In the present work, we found superior tensile strength, hydrophobic and antibacterial activities in graphene incorporated polyvinyl alcohol (PVA) based nanofibers, prepared by electrospinning. A series of ultrafine graphene-based ink (G-Ink) incorporated PVA nanofiber (GPN) with different concentrations of graphene (0, 0.008, 0.02, 0.04, 0.06, and 0.08% w/v) was fabricated. To overcome difficulty in direct dispersing graphene into the PVA solution, we have prepared graphene-based ink for dispersing into polymer solution. The morphology, composition, mechanical behaviour, and surface wettability of these membranes was investigated. The Fourier transform infrared spectra and the Raman spectra confirmed the successful incorporation of graphene into the GPN. Graphene when used as a nanofiller in polymers, provides excellent mechanical properties (814%), hydrophobicity (40%), and antibacterial properties. In the current study we tested GPN membranes for preserving two fast rotting foods like coriander leaves and tomato. We found that GPN membrane can be used safely for food packaging applications to increase the shelf life of perishing food items, such as up to 3 days for coriander leaves and 8 days for tomatoes.

Influence of different bio‐based and conventional packaging trays on the quality loss of fresh cherry tomatoes during distribution and storage

AbstractThe quality loss and shelf life of cherry tomatoes stored in different types of commercially available bio‐based packaging trays were analysed and compared with the reference materials, corrugated cardboard and recycled polyethylene terephthalate (rPET). During storage under conditions reflecting points in a regional German supply chain, typical quality parameters were investigated. Surface bacterial counts of the packaging materials were investigated before and after storage, and material parameters were determined for selected packaging.The results showed that groundwood pulp and sugar cane trays showed higher preserving characteristics of tomatoes in comparison with the references. During storage, weight loss was highest for tomatoes stored in polylactic acid (PLA). The highest increase in microbial count with 3.5 log10 units was observed after 20 days for tomatoes stored in packaging trays of bamboo. The lowest increase with 0.5 log10 units and 0.6 log10 units was recorded for tomatoes stored in packaging trays of groundwood pulp and grass paper, respectively. The results of the packaging parameters show the highest (411.0 N) and lowest (79.0 N) tensile strength for cellulose and groundwood pulp. The water absorption capacity ranged from <10 g/m2 (bamboo, cellulose) up to 211.2 g/m2 (corrugated cardboard).

Room Temperature Growth of Salmonella enterica Serovar Saintpaul in Fresh Mexican Salsa

Salsa-associated outbreaks, including the large multistate outbreak in the United States in 2008 caused by jalapeño and serrano peppers contaminated with Salmonella Saintpaul, have raised concerns about salsa as a potential vehicle for transmission. Despite these events, there has been relatively limited research on the potential growth of pathogenic bacteria in salsa. The aim of this study was to characterize the survival and growth of Salmonella, including the outbreak strain of Salmonella Saintpaul (E2003001236), in freshly made salsa and its main ingredients. Chopped tomatoes, jalapeño peppers, cilantro, and onions were tested individually or mixed according to different salsa recipes. Samples were inoculated with five Salmonella serotypes at 3 log CFU/g: Saintpaul (various strains), Typhimurium, Montevideo, Newport, or Enteritidis. Samples were then stored at room temperature (23°C) for up to 12 h or 3 days. The Salmonella Saintpaul levels reached approximately 9 log CFU/g after 2 days in tomato, jalapeño pepper, and cilantro. Growth was slower in onions, reaching 6 log CFU/g by day 3. Salsa recipes, with or without lime juice, supported the growth of Salmonella Saintpaul, and final levels were approximately 7 log CFU/g after 3 days at 23°C. In contrast, the counts of Salmonella Typhimurium, Salmonella Montevideo, Salmonella Newport, and Salmonella Enteritidis increased only 2 log CFU/g after 3 days in any of the salsas. Other Salmonella Saintpaul strains were able to grow in salsas containing 10% lime juice, but their final levels were less than 5 log CFU/g. These findings indicate the enhanced ability of the Salmonella Saintpaul outbreak strain to grow in salsa compared with other Salmonella strains. Recipe modifications including but not limited to adding lime juice (at least 10%) and keeping fresh salsa at room temperature for less than 12 h before consumption are strategies that can help mitigate the growth of Salmonella in salsa.

Development and Evaluation of Pilot Scale Modified Atmosphere Storage and Modified Atmosphere Packaging Systems for Tomatoes

A pilot scale modified atmosphere storage (MAS) structure of 100 kg and modified atmosphere packaging (MAP) of 1 kg capacity have been designed and developed for the storage of tomatoes. A polymeric film (LDPE + LLDPE, 80 µ thickness) has been used as the lining material to act as a regulator for the transport of gases and water vapor. The retail size MA packaging study of medium-size tomatoes were taken and packed in 80 µm (LDPE + LLDPE) polymeric film (size: 25 × 22 cm2) so as to compare with the quality of MAS system. The quality analysis revealed that the parameters namely physiological loss in weight (PLW), firmness, color (L*, a*, b*), TSS, and titratable acidity were found to be 0.3%; 45.88 N; 60.23, − 3.25, 32.16; 4.3; and 0.55 of tomatoes after 21 days of storage in MAS system at ambient temperature (25 °C), respectively, which is comparable with the quality parameters at harvesting maturity and 1 kg MA package. The MAS system increased the shelf life from 7 to 21 days for tomatoes, at ambient temperature. However, the shelf life was achieved up to 35 days at 10 °C in MAS for tomatoes. Thus, developed structure is highly beneficial in retailing and transportation of tomatoes.

Vegetable Cultivation under Hydroponics in Himalayas : Challenges and Opportunities

<p>Defence Institute of Bio-Energy Research, Haldwani has successfully developed a hydroponics system by clubbing the soil less cultivation with rain water harvesting technology. The institute has also developed a suitable nutrient composition suitable for wide range of vegetables. Among the various varieties/hybrids grown in hydroponics, cucumber line PC 4C-8 exhibited the maximum fruit yield (448.3 q/ha). Among the various tomato hybrids, Avinash-2 exhibited highest yield (1052 q/ha) and number of fruits (154 per sq m) whereas TSS, total sugars, crude protein and minerals content were the maximum in tomato hybrid DARL-304. Interestingly, hydroponics system prolonged the harvesting period by 45 days in tomato. Plant population density of 6 plants/m2 was found optimum with the highest fruit yield in tomato and cucumber. Tomato hybrid DARL-304 exhibited higher fruit yield (6.5 kg/plant). Hydroponics system have been found successful in Auli (9000’ MSL), Joshimath with fruit yield of 2.25 kg/plant to 3.79 kg/plant in tomato. The yield was higher in rain water as comparison to river water. The article deals with the hydroponics technology in detail vis-à-vis efforts made at DIBER for standardization of hydroponics technology. It is envisaged that experience gained in successful cultivation of various crops in hydroponics using single nutrient solution at various altitudes through research stations of the institute.</p>

Supercritical fluid chromatographic-tandem mass spectrometry method for monitoring dissipation of thiacloprid in greenhouse vegetables and soil under different application modes

A rapid, sensitive and effective supercritical fluid chromatographic-tandem mass spectrometry (SFC-MS/MS) method was developed to analyze thiacloprid for the first time. The SFC-MS/MS conditions were optimized with the ultra-performance convergence chromatography (UPC2) BEH column (100 mm × 3.0 mm, 1.7 μm particle size) and thiacloprid was eluted at 1.22 min in gradient mode with CO2/methanol as mobile phase. The 0.1% formic acid in methanol (v/v) was used as postcolumn compensation solution to improve sensitivity. The ABPR pressure, flow rate of mobile phase and flow rate of compensation pump were set at 1800 psi, 1.8 mL/min, and 0.1 mL/min, respectively. The average recoveries of thiacloprid in soil at four spiking levels (5, 10, 100, 1000 μg/kg) ranged between 78.8% and 107.1% with relative standard deviations (RSDs) lower than 12.2% and the limit of quantitation (LOQ) was 5 μg/kg. The proposed method can distinctly improve the analysis efficiency by 2–12 times and reduce the solvent consumption by 5%–95% compared with reported methods. It was applied to investigate the dissipation rates of thiacloprid in greenhouse vegetables and soil under different application modes. The half-lives of thiacloprid in cucumber and soil were 9.55–20.44 days and 3.74–9.14 days separately under different application modes, 10.60 days in tomato under foliar spraying. The residues in vegetables under root irrigation were all less than that under foliar spraying. The results could offer useful data for risk assessment of thiacloprid in agricultural production.

Field investigations of dissipations and residues of cyazofamid in soil and tomato: risk assessment of human exposure to cyazofamid via tomato intake.

Cyazofamid, as a fungicide of the novel cyanoimidazole chemical class, has been widely used to control tomato late blight. Understanding of cyazofamid residues in environment and crops is an essential prerequisite for its risk assessment. In this study, field investigations in four typical tomato-producing areas were conducted to explore the dissipation kinetics and residues of cyazofamid and its primary metabolite 4-chloro-5-p-tolylimidazole-2-carbonitrile (CCIM) in soil and tomato. A robust method using QuEChERS coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for simultaneous analysis of cyazofamid and CCIM, with limits of quantification of 0.33 and 3.8μg/kg, respectively. Field trials showed that the half-lives of cyazofamid were 3.6-6.9days in soil and 12.2-18.3days in tomato. The total residues of cyazofamid and CCIM in tomato collected at three time intervals were all below 0.5mg/kg. Moreover, the potential risks of total residues via tomato intake to ten population subgroups were evaluated. We found that the risk quotient values were all generally low (0.13-1.3%), indicating that the recommended dose of cyazofamid on tomato will not result in a consumer exposure exceeding the toxicological reference value. Here, the results of field investigation provided important information for further understanding the behavior and risk of cyazofamid in the natural environment.

Degradation profile and safety evaluation of methomyl residues in tomato and soil

Summary A high performance liquid chromatography with the photodiode array detector (HPLCDAD) analytical method was developed to determine the residue levels and investigate the dissipation pattern and safety use of methomyl in tomato and soil. Methomyl residues were extracted from tomato and soil samples with ethyl acetate. The extract was cleaned up with the QuEChERS method. The results showed that the average recoveries were in the range of 87.1-94.5%, with RSD of 6.9-11.2%. Limits of detection (LOD) and quantification (LOQ) were 0.005 and 0.007 mg/kg, respectively. The residue levels of methomyl were best described to first order rate kinetics and half-lives ranged from 1.34 to 1.8 days in tomato and soil, respectively. The theoretical maximum residue contributions for methomyl on tomato were found to be less than the maximum permissible intake values even on zero days, therefore consumer health risks are minimal at the recommended dose on tomato.

Dissipation of deltamethrin, triazophos, and endosulfan in ready mix formulations in tomato (Lycopersicon esculentum L.) and Egg plant (Solanum melongena L.).

Persistence of delltamethrin, endosulfan, and triazophos in egg plant and tomato was studied following application of two ready mix formulations of insecticides viz. deltametrhin and endosulfan (Cobra 5000; 0.75% deltamethrin + 29.5% endosulfan) and deltamethrin and triazophos (Annaconda Plus; 1% deltamethrin + 35% triazophos) at recommended (1.0 L/ha and double dose 2.0 L/ha). The residues of deltamethrin persisted till 7 and 5 days in tomato and egg plant fruits, respectively, in the ready mix formulation of Cobra 5000 whereas endosulfan persisted till 15 and 10 days in tomato and egg plant fruits, respectively. Dissipation of the insecticides followed first-order kinetics with half-life values of deltamethrin and endosulfan ranged from 2.6 to 4.7 and 1.4 to 1.7 days, respectively, for both the vegetables. In case of combination mix of deltamethrin and triazophos (Annaconda Plus), deltamethrin persisted beyond 5 days in both tomato and egg plant fruits, while triazophos persisted till 10 days in both the vegetables. Residues of deltamethrin and triazophos dissipated with half-life of 2.6-4.2 and 1.7-4.1 days, respectively, on tomato and egg plant fruits. Based on the Codex MRL limits, a safe waiting period of 5 and 3 days is suggested for tomato and egg plant, respectively, for the ready mix formulation of deltamethrin and endosulfan (Cobra 5000), and 5-day waiting period is suggested for tomato and egg plant for the combination mix of deltamethrin and triazophos.

The influence of bio-phyto-modulators in the biological development of seed germination in tomato and pepper plants.

The objective of the research was to observe the influence of A.D. type bio-phyto-modulators uponseed germination and plant biology. The biological material subject to analysis was represented by Coralvariety of tomato and hybrid Blondy F1 pepper seeds. As part of this experiment DEA A.D. type biophyto-modulators has been used. For germination rhythm determination was used one version in 4replications with 15 seeds each, which was attached a DEA type device and one control version, with nodevice attached. In the fourth day from seeding in variant with the tomatoes and DEA, the first plantsappeared, and until the sixth day all of the 15 seeds were germinated. The germination for “witness”variant began as late as day six and finished in tenth day. For the pepper seeds the sample with DEAbegan germination in the eighth day and ended in twelfth day while “the witness” began germinationin the twelfth day and ended in the fifteenth. We can see that in both cases where was located the DEAtype device germination occurred faster than normal germination time 6-8 days for tomatoes and 10-14 days for peppers. Using AD type bio-phyto-modulators brought a beneficial contribution increasinggermination speed for both species.

Dissipation rate and residue distribution of dufulin in tomato and soil under field conditions.

Dissipation rate and residue distribution of dufulin in tomato and soil under field conditions were investigated in Guiyang, Tianjin, and Haikou during 2011-2012, using ultra-performance liquid chromatography. Average recoveries of dufulin in tomato and soil ranged from 91.03 % to 95.16 % and 94.35 % to 98.34 %, respectively, with relative standard deviations of 1.16 %-3.97 %. Dufulin dissipation followed first-order kinetics. Dufulin had half-lives of 2.8, 4.7, and 9.0 days in tomato and 6.1, 8.2, and 17.2 days in soil in Guiyang, Tianjin, and Haikou, respectively. At harvest, dufulin residues in tomato samples collected 5 days after the last application at 3 times recommended dosage applied every 5 days were below 1.0 mg kg(-1).

Efficacy of evaporative cool chamber in pasighat condition, Arunachal Pradesh, India

Effectiveness of low cost cool chamber-an on-farm rural oriented storage structure which operates on the principle of evaporative cooling developed at IARI, New Delhi was studied under Pasighat condition. Freshly harvested vegetables viz. brinjal, frenchbean, green chillies, coriander and tomatoes were subjected to storage in evaporative cool chamber and ambient condition. The average minimum and maximum temperatures during storage period at cool chamber were 20.4°C and 30.23°C respectively and relative humidity were 74% and 95%, respectively. The minimum and maximum temperatures during storage at room temperature condition were 26.1°C and 31.8°C respectively and relative humidity were 59% and 79% respectively. Results indicate that storage at cool chamber increases the shelf life of all the vegetables by considerably reducing the physiological loss in weight (PLW), retaining sensory quality like colour, texture and increases marketability. Cool chamber was suitable for storing brinjal for 9–15 days, beans and green chillies for 8–10 days, coriander for 3 days and tomatoes for 14–15 days as against 4–5 days for brinjal, beans and green chillies, 1 day for coriander and 7 days for tomatoes in room condition.

Degradation of Propamocarb-hydrochloride in Tomatoes, Potatoes and Cucumber Using HPLC–DAD and QuEChERS Methodology

Propamocarb-hydrochloride is a widely used fungicide around the world. The dissipation of propamocarb-hydrochloride in tomatoes, potatoes and cucumber were evaluated. QuEChERS methodology before quantification using HPLC-DAD was used. Preharvest interval and maximum residue limit were 4 days and 1.0 mg kg(-1) for tomatoes, 3 days and 0.5 mg kg(-1) for potatoes and 7 days and 1.0 mg kg(-1) for cucumber. Half-lives (t(1/2)) were 1.29, 2.26 and 9.05 days for tomatoes, potatoes and cucumber, respectively.

Residues and Dissipation Dynamics of Fosthiazate in Tomato and Soil

Residue dynamics of fosthiazate in tomato and soil was studied in this paper utilizing liquid chromatography with tandem mass spectrometry (LC-MS/MS). The field trial was conducted in three sites: Beijing, Liaoning, Hubei in China. Fosthiazate dissipated with the half-life 0.75-2.6days in tomato or tomato plants and 2.5-11.6days in soil. In the terminal residue experiment, no higher residue than 0.023mgkg(-1) in tomato and 0.27mgkg(-1) in soil was detected. Residues of fosthiazte in tomato were far below Japan maximum residue levels (0.2mgkg(-1)).

Clothianidin dissipation in tomato and soil, and distribution in tomato peel and flesh

Clothianidin, a new neonicotinoid insecticide, was systematically evaluated. An analytical method using gas chromatography with electron capture detection was developed. Recoveries were between 92% and 102%, with relative standard deviations from 3% to 5% at three fortified levels. The decrease of clothianidin in tomato and soil samples under field conditions at Beijing, Shandong, and Anhui were determined. The dissipation rates of clothianidin fit first-order kinetics. Its half-lives ranged from 6.7 to 12.7 days in soil, and 7.0 to 11.9 days in tomato. On the suggested pre-harvest interval of 7 days, the distribution of clothianidin in tomato peel and flesh was studied. Most residues were found on the peel. Hence, removing the tomato peel before consumption is advisable. The stability of clothianidin fortified at 0.3 or 3mg/kg in frozen green and red ripe tomatoes was also determined. The half-life mainly depended on the spiked levels of this pesticide.

A gas chromatographic method for the determination of the fungicide chlorothalonil in tomatoes and cucumbers and its application to dissipation studies in experimental greenhouses

A new method to evaluate the levels of residue and the dissipation of chlorothalonil fungicide in tomatoes and cucumbers grown in experimental greenhouses was developed and validated. The vegetables were submitted to a single spraying with chlorothalonil at half, equal to and double of the recommended dose. Chlorothalonil residues were extracted in Ultra-Turrax system using ethyl acetate in the presence of anhydrous sodium sulphate and determined by gas chromatography with electron capture detection. The analytical curves were linear from 0.005 to 5.0 mg L-1, with coefficient of determination higher then 0.995. The assays provide acceptable results with RSD values below 10.5% and recoveries were between 92.2 and 114.5% for tomatoes, and between 86.2 and 103.3% for cucumbers, both obtained from spiked samples at 0.028, 0.28, 2.8 and 5.0 mg kg-1 levels. Statistical interpretation of residue levels fitted to a first-order model for the dissipation behavior of chlorothalonil. The mean half-life after treatments at the recommended dose, in the two experimental years, was 8.8 days for tomatoes and 1.6 days for cucumbers. The higher decrease rate of chlorothalonil residues in cucumbers is mainly due to the higher growth rate of this vegetable relative to tomato. The developed method has proven to be efficient for the determination of chlorothalonil residues in tomatoes and cucumbers with a limit of quantification of 0.02 mg kg-1 level, permitting to evaluate the risk of consumer exposure to these residues.

A Universal Expression/Silencing Vector in Plants

A universal vector (IL-60 and auxiliary constructs), expressing or silencing genes in every plant tested to date, is described. Plants that have been successfully manipulated by the IL-60 system include hard-to-manipulate species such as wheat (Triticum duram), pepper (Capsicum annuum), grapevine (Vitis vinifera), citrus, and olive (Olea europaea). Expression or silencing develops within a few days in tomato (Solanum lycopersicum), wheat, and most herbaceous plants and in up to 3 weeks in woody trees. Expression, as tested in tomato, is durable and persists throughout the life span of the plant. The vector is, in fact, a disarmed form of Tomato yellow leaf curl virus, which is applied as a double-stranded DNA and replicates as such. However, the disarmed virus does not support rolling-circle replication, and therefore viral progeny single-stranded DNA is not produced. IL-60 does not integrate into the plant's genome, and the construct, including the expressed gene, is not heritable. IL-60 is not transmitted by the Tomato yellow leaf curl virus's natural insect vector. In addition, artificial satellites were constructed that require a helper virus for replication, movement, and expression. With IL-60 as the disarmed helper "virus," transactivation occurs, resulting in an inducible expressing/silencing system. The system's potential is demonstrated by IL-60-derived suppression of a viral-silencing suppressor of Grapevine virus A, resulting in Grapevine virus A-resistant/tolerant plants.

Natural transformation-based foreign DNA acquisition in a Ralstonia solanacearum mutS mutant

Mutator strains with defective methyl-mismatch repair (MMR) systems have been shown to play an important role in adaptation of bacterial populations to changing and stressful environments. In this report, we describe the impact of mutS::aacC3-IV inactivation on foreign DNA acquisition by natural transformation in the phytopathogenic bacterium Ralstonia solanacearum. A mutS mutant of R. solanacearum exhibited 33- to 60-fold greater spontaneous mutation frequencies, in accordance with a mutator phenotype. Transformation experiments indicated that intra- and interspecific DNA transfers increased up to 89-fold. To assess horizontal gene transfer (HGT) from genetically modified plants to R. solanacearum, fitness of the mutator was first evaluated in soil and plant environments. Competitiveness was not modified after 61 days in soil and 8 days in tomato, and the progress of plant decay symptoms was similar to that of the wild-type strain. Despite its survival in soil and in planta, and the powerful capacities of HGT, R. solanacearum was not genetically transformed by transgenic plant DNA in a wide range of in vitro and in planta tests.

Management of phytotoxicity of cobalt in tomato by chemical measures

Tomato ( Lycopersicon esculentum) cv. Alivikas was grown in refined sand at two levels of phosphorus (P), adequate (1.5 mM) and high (3.0 mM) each at excess (0.5 mM) cobalt (Co), supplied as cobalt sulphate. Apart from its own toxicity symptoms, excess Co induced iron (Fe) deficiency symptoms on young leaves after 6 days of metal supply. In addition excess Co decreased the biomass, concentration of Fe in different parts, chlorophyll a and b, Hill reaction activity and catalase activity and increased that of peroxidase, acid phosphatase, ribonuclease, Co concentration in various parts, carbohydrate and phosphorus fractions in leaves, more effectively at adequate than high P. High P had no harmful effects of its own on growth and metabolism of tomato. Withdrawal of excess Co after 12 days in tomato partially increased the biomass, concentration of proteins, chlorophyll a and b, Hill reaction activity and lowered the accumulation of sugars, starch, inorganic, organic phosphorus fractions and stimulated activity of acid phosphatase, peroxidase and ribonuclease more at adequate than high P. Addition of Fe along with excess Co ameliorated the effects of excess Co by partially increasing the biomass, concentration of chlorophyll a and b, iron, proteins, Hill reaction activity and catalase activity and elevated the accumulation of carbohydrates. Withdrawal of excess Co from tomato ameliorated the toxic effects of cobalt more effectively than application of iron (0.5 mM) as iron increased its own availability but failed to reduce the accumulation of Co, carbohydrate and phosphorus fractions.