Gobio

Georgina Cundall asked:




Eating fruits and vegetables is one of the best ways to maintain good health. Fruits and vegetables are an important part of a healthy diet. They contain vitamins, phytochemicals, and minerals that can protect your body from diseases like diabetes, cancers, and heart diseases. Ideally, you should consume five kinds of vegetables and two kinds of fruits each day.

Doctors and health practitioners recommend increasing the fruit and vegetable servings at your table. But, it sometimes proves difficult on your household budget to purchase increased amounts of vegetables and fruits.

These tips can help you to fit a variety of vegetables and fruits within your existing household budget with some planning and foresight.

If you live near a farm, purchase your weekly supply of fruits and vegetables from the farmer. Alternatively, you can plan your shopping for the end of market day.

Normally, vendors prefer selling their wares at discounted prices at the end of the market day rather than taking the leftover produce back home.

Always buy the seasonal produce of fruits and vegetables. These are comparatively cheaper than out of season produce. Clementines or tiny tangerines are cheaper during Christmas while pears and apples are cheaper during the fall.

Some farms offer sale of produce through a program called Community Supported Agriculture (CSA). Pay the annual fee up-front to become a member of this program.

You may then receive boxes of the growing produce regularly, such as every week.

Most grocery stores offer weekly sales. Try purchasing only the fruits and vegetables available on this sale list to benefit from the discounted prices or through special rebates available on this produce. You get to enjoy a variety of fruits and vegetables without it being a burden on your budget.

Another way of saving on grocery budget is to make bulk purchases. Most wholesalers offer heavy discounts if you purchase fruits and vegetables in bulk. Go shopping with a neighbor or a friend and split your purchases. You get to enjoy various fruits and vegetables at much lower prices.

Frozen fruits and vegetables are sometimes cheaper than fresh vegetables and fruits. Many are under the wrong impression that frozen fruits and vegetables are low on nutrients. The nutrient value is claimed to remain much the same in frozen and fresh fruits and vegetables.

When choosing and buying frozen fruits, it is best to go for store brands. Most stores run sales most of the time when you may get your stock of vegetables and fruits at nominal costs.

Sometimes, it may be best to get frozen fruits and vegetables if they are not grown locally and have to be shipped from great distances.

If you purchase both frozen and fresh produce, make sure that you use your fresh produce earlier than the frozen ones. Frozen ones will stay good for a much longer period than the fresh fruits and vegetables.

Another way of saving on your grocery budget is to buy fruits and vegetables and chop it yourself instead of purchasing pre-chopped vegetables.

Purchase vegetables without any seasonings like salt, butter, or sauces. It is always best to add all seasonings just before you have your meal, or according to your taste.

It therefore is not any extra burden use these tips to include more vegetables and fruits in your diet.

Just plan carefully and make your purchases accordingly to get the best out of every dollar you spend on your fruits and vegetables.

To find out more fabulous information about how to incorporate a healthy lifestyle with more fruits and vegetables order your copy of Fabulous Fruit and Vegetables today.

Fred Myers asked:


The growing of vegetables is less difficult than other types of plants. You can easily accomplish this with just a little planning,proper planting and some care for those vegetables you selected to plant.

The very first considerations are how much time do you have to devote to the gardening project.  This will certainly dictate how much or little you will be planting. What is the size of the area you can easily convert to garden if you don’t already have a plot in the works? You must take into consideration the type of climate in your area. The growing of your vegetables will certainly be effected by your temperate zone as many areas of the world cross over dozens of temperature zones.

The location of your garden is the next consideration. You need to think about the shade of the area and maybe even the wind that prevails over the selected location. Your vegetable garden will like at least five hours of sunlight per day regardless of the type of vegetables you plan to raise but ten hours is ideal. The other thought to keep in mind when planting your vegetable garden is the height of each plant. For example don’t plant corn,which is tall,where it will shade the other lower vegetables. Always plant taller vegetables like corn to the north of the shorter vegetables. Your lettuce needs to be near the southern part of the garden.

It is not a good idea to place your vegetable garden in a low spot,or at the bottom of a hill or especially at the base of a sloping area which is bordered by a solid fence. These areas tend to warm up very slowly in the spring. It is also easy for frost to form in these areas since cold air is naturally present in these low areas.

Your vegetable garden will flourish best in a level section with good drainage and good loose soil. It is best not to locate the vegetable garden in an area which is littered with rocks and stones for two reasons. Vegetables will have a difficult time of it in endeavoring to root and you will have little fun in preparing the area to plant your vegetables. It is also important to locate the garden so that water is easily accessible. You might need to engage a length of hose to reach the garden which is ok. It is not ok if the location means dragging water to the site.

In order to arrive at the types of vegetables you can grow,after personal preference,you must know what type of soil in which the seeds will be planted. A simple and very inexpensive soil testing kit will provide you with the answer.It will test for levels of nutrients and most important the ph. There are vegetables that desire a more acidic soil while other vegetables prefer an alkaline soil. Most vegetables enjoy a range of 6.0 to 6.5 when it comes to ph. All of this can be handled by use of compost added to the topsoil or you can add commerical fertilizer to the soil to improve whatever the results of your testing produced. You can usually find the soil conditions required on the seed packet or ask the garden center if you are purchasing plants.

In regards to watering,approximately an inch of water per week is good for most vegetable gardens. The amount can vary based on the type of soil you have used to plant your vegetables. Example clay soil will remain wetter than loamy soil and sandy soil will require more water than either of the aforementioned two.

If you are interested in a lot of detail concerning planting of vegetables and the planting of many different types of vegetables then you need to visit this web page below at gardenersgardening for more information

 

 

Ranjith asked:


There are a lot of vegetable exporters and also they had given a great hand to the Indian exporting system. Vegetable exporting is one of the most important crops for the developing country like India. Vegetable exporters in India are concentrating mainly in the vegetable such as onion, carrot, French beans, potato, lemon, tapioca, tomato, etc…

In these vegetables onion stands first in exporting because onion cultivation is large in amount moreover India is the world’s largest country in exporting onions to all over the world. Because of these reasons all leading vegetable exporters give more attention in the onion. Among all vegetables onion needs low capital during the time of cultivation. So it makes larger profit to the vegetable exporters. There is a variety of onion for export. Red onions rose onions, podisu onions are the main category.

Another important crop for vegetable exporting is carrot. Vegetable suppler gives more attention for fresh carrots. A different variety of carrots are available in the Indian market and they are exported to the international market in reasonable rate. Most of the people from the entire world depends upon the Indian market for good quality stuff so the vegetable supplier in India looking care about the quality of the vegetable. French bean is another exporting vegetable; from the Indian market people can get good quality fresh green beans. This is highly nutritious and makes the man healthy.

Tapioca is another exporting vegetable. A large quantity of high quality tapioca is exporting from the Indian market. Tapioca is cultivated in large scale in India that is nearly 3 lakhs hectares. The vegetable exporter or vegetable supplier India exports normal tapioca and frozen skin-peeled Tapioca to the people.

In Indian market we can see a large variety of tomato and they are tasty also have high nutritious value. Capsicum is another exporting vegetable from India. The vegetable suppliers supply different varieties of capsicums like in different colors that are in red, yellow, and green. They supply capsicum to several countries in several continents.

One of the export vegetable in India is Chilly. There are a collection of different chilly can find in the Indian market. These different types of chilly are exported by the vegetable suppliers to all over the world.

Hence the vegetable products are leading Indian economy a lot. The vegetable suppliers are giving more attention to the high quality stuff and good packing of vegetables.

For more Information Vegetable Expoter, Supplier India

Md. Wasim Aktar asked:


Preferably, RAC samples used in processing studies should contain field treated quantifiable residues as close as possible to the MRL, so that measurable residues are obtained, and transfer factors for the various processed commodities can be determined. A transfer factor gives the ratio of the residue concentration in the processed commodity to that in the RAC. For example if the residue concentration is 0.5 mg/kg in olives and 0.2 mg/kg in olive oil, the transfer factor is 0.2/0.5=0.4. A factor 1 (= concentration factor) indicates a concentration effect of the processing procedures. Enhancing the residues either by increasing the application rates, shortening the pre-harvest interval (PHI) or spiking the RAC with the active ingredient and its metabolites in vitro is not, as and rule, desirable. Spiking is only acceptable if the RAC residues can be shown to consist only of surface residues. However, in some cases, especially where residues in the RAC are close to the analytical limit of determination, field treatment at exaggerated rates or shortened PHIs is advisable to obtain sufficient residue levels for the processing studies.

The first step in household or commercial food processing is the preparation of food using various mechanical processes, such as removing damaged or soiled items or parts of crops, washing, peeling, trimming or hulling. This often leads to significant declines in the amount of pesticide residues in the remaining edible portions (Petersen et al., 1996; Celik et al., 1995; Schattenberg et al., 1996).

WASHING

Household washing procedures are normally carried out with running or standing water at moderate temperatures. Detergents, chlorine or ozone can be added to the wash water to improve the effectiveness of the washing procedure (Ong et al., 1996). If necessary, several washing steps can be conducted consequently.

The effects depend on the physiochemical properties of the pesticides, such as water solubility, hydrolytic rate constant, volatility and octanol-water partition coefficient (Pow), in conjunction with the actual physical location of the residues; washing processes lead to reduction of hydrophilic residues which are located on the surface of the crops. In addition, the temperature of the washing water and the type of washing has an influence on the residue level. As pointed out by Holland et al. (1994), hot washing and the addition of detergents are more effective than cold water washing. Washing coupled with gentle rubbing by hand under tap water for 1 min dislodges pesticide residues significantly (Barooah and Yein, 1996). Systemic and lipophilic pesticide residues are not removed significantly by washing.

Table (1) shows examples of the effects of washing on the residue levels of different pesticides applied to fruits and vegetables.

PEELING

The outer leaves of vegetables often contain residues of pesticides applied during the growing season. Therefore, peeling or trimming procedures reduce the residues levels in leafy vegetables. Peeling of root, tuber and bulb vegetables with a knife is common household practice. Many examples show that most of the residues concentration is located in or on the peel. Peeling of the RACs may remove more than 50% of the pesticide residues present in the commodity. Thus, removal of the peel achieves almost complete removal of residues, so leaving little in the edible portions. This is especially important for fruits which are not eaten with their peels, such as bananas or citrus fruits. Reynolds (1996) showed that peeling or trimming of carrot reduced the residues of chlorfenvinphos, primiphos-methyl, quinalphos, triazophos resulting a transfer factor of 0.2. However, the peel from commercial peeling processes can be used as animal feed or for the production of essential oils (citrus) or pectin (citrus, apple etc.). For such industrial processes, it is important to realize that especially non-systemic surface residues are often concentrated in the peel. For systemic pesticides, peeling may not be as effective as shown by Sheikhorgan et al (1994). After application of thiometon on cucumbers, no reduction of residue levels could be detected in the peeled cucumbers.

Under the Codex Alimentarius, as in other international standards, MRLs refer to the whole fruits, which is appropriate for assessing compliance with GAP. These MRLs are of limited significance, however, in assessing dietary exposure to pesticides from fresh fruits, which are peeled (Holland et al.,1994).

COOKING

Cooking procedures at different temperatures, the duration of the process, the amount of water or food additives, and the type of system (open or closed) may have an impact on the residue level. Normally, residues are reduced during the cooking process by volatilization in open systems or by hydrolysis in closed systems. In any case, adding cooking liquid dilutes the residues. Several studies were reported on the dissipation of pesticides in crops during cooking. In addition to the studies summarized in table 1 the behavior of the organophosphorus pesticides chlorfenvinphos, fenitrpothion, isoxathion, methidathion and prothiophos during cooking was examined by Nagayama (1996) with green tea leaves, spinach and fruits. These pesticides decreased during the cooking process corresponding to the boiling time. According to their water solubility, some pesticides were translocated from the raw materials into the cooking water. On the other hand, the pesticide remained in the processed food according to their octanol-water partition coefficient, which is an indicator of hydrophilic or lipophilic properties of the compound. In exceptional cases, cooking processes may cause pesticide degradation, yielding a reaction product of toxicological significance. For e.g., daminozide is degraded to UDMH (1, 1-dimethylhydrazine), which is much more potent than the parent compound (Leparulo-Lofus et al.,1992). Another example is the formation of ETU (Ethylenethiourea) from EBDCs (Ethylene bisdithiocarbamate) fungicides like mancozeb, during heating processes (Petersen et al., 1996).

Dipping in chemical solution

Sodium chloride solution is largely used to decontaminate the pesticide residues from different fruits and vegetables .there are several studies to prove the efficacy of salt water washing to dislodge the pesticides from crops. In this process, sample of chopped fruits and vegetables is put in a beaker containing 5% sodium chloride solution. After 15 minutes the plant samples are gently rubbed by hand in salt solution and alt water is decanted. The examples of the effect of salt solution treatment on the residue levels of different pesticides applied to vegetables have been shown in table 1.

Kumar et al (2000) reported that dipping of green chillies in 2% salt solution for 10 minute followed by water wash prove to be effective, facilitating the removal of 32.56 and 84.21% residues correspondingly at 0 and 5 days after spray of triazophos (700g a.i./ha) while the acephate residues were removed to an extent of 78.95% at zero day. Following same technique Kumar et al (2000) observed the 90.56 and66.93% reduction correspondingly on 0 and 5 days after spraying of cypermethrin in chillies.

Dip treatment of fruits in NaCl solution, HCl, acetic acid, NaOH solution, potassium permanganate removed 50-60% of surface residues of synthetic pyrethroids compared to 40-50% removal by hydrolytic degradation with NaOH (Awasthi, 1986b).

Water solution of NaOH, acetic acid potassium dichromate and soap solution used as decontaminating agents for tom ………….

The treatment of fruits with 2% tamarind solution dip for 5 minute followed by tap water wash and steam cooking for 10 min. was found to remove the residues of monocrotophos, carbaryl and fenvalerate to an extent of 41.81, 100 and 100% respectively. Treatment with 2% salt solution was equally effective.

Dip treatments of the brinjal fruit wioth water, sodium chloride, HCl solution, acetic acid solution or potassium permanganate solution were all found to remove 30-33% of the residues of fenvalerate, permethrin, cypermethrin and deltamethrin; NaOH solution 40-45% and Teepol (a detergent) solution 50-60%. The effect of washing in reducing the residues decreased progressively at the second and third harvests.

Many experiments were carried out with the three common household preparations viz. washing with water, salt water washing and cooking to ***** their relative efficiencies in reducing the pesticide residues in different vegetables. The results have been summarized in the following table.

Table: Effect of washing, salt water washing and cooking on pesticide residue levels.

Crop Pesticide % of Residue dislodged * Result Reference

Washing with

water Salt water washing Cooking

Cauliflower Methamidophos 41-48 46-47 46.94

-53.54 Largest reduction was brought about by cooking. Jacob and Verma (1990)

Okra

Methamidophos

64-72

19-58

58-64 Washing with water could remove maximum residues indicating its maximum solubility in water though all the processes lower down the TMRL values. Jacob and Verma (1990)

Cauliflower Alpha-cypermethrin

7-38 _

12-17 Washing was found to be more efficient than cooking probably due to the thermal stability of cypermethrin. Malik et al (1997)

Cabbage

Chlorpyriphos

Quinalphos

38

41

52.13

56.50

54.3

55 With the three processes residues were reduced to some extent. They can not reduce the residue below the MRL. Thus a waiting period of a minimum of one and two weeks, respectively, was suggested irrespective of washing cooking for quinalphos and chlorpyriphos on cabbage. Nagesh and Verma (1997)

Cow pea

Metasystox

Carbalyl

84.3

87.5

86.4

88.7

83.4

80.8 Only boiling of the pod samples could decontaminate the residues present of surface or inside the tissue to the extent of safe limits by 10th day of treatment. Dikshit et al (1984)

Cauliflower

Malathion

60

70

80 Cooking was found to be most effective and lowered the TMRL value from one week to zero days. Jacob and Verma (1989)

Bhindi

Quinalphos

61.84-64.35

43-53

78-82

Both washing with water and salt water washing brought down the residues below the MRL at zero days, cooking also did this resulting maximum reduction of residues.

Jacob and

Verma (1985)

Cabbage

Malathion

Carbaryl

Pyrethroids

64.60

75.40

22.06 (av.)

-

-

-



83.97

89.62

56.72 (av.)

The extent of decontamination was higher due to cooking compared to washing for all insecticides.

Bhatia and

Verma (1994)

Leaves and curds of cauliflower heads of cabbage and pods of Indian colza

Green beans

Methamidophos

DDT

Malathion

Carbaryl



65.71-77.67

71

96

52



-

-

-

-

80-88.88

52(cooked)

66 (pressure cooked)

99(cooked)

99(p.cooked)

77cooked

69(p.cooked)



Cooking dislodges maximum residues.

Water wash removed maximum DDT residues whereas cooking is effective to remove malathion and carbaryl residues.

Dikshit et al (1986)

Elkins et al (1968)

From the above table it can be said that cooking is most effective to reduce the residues of different pesticides from various vegetables though in some cases washing with water was found to be effective to reduce the initial residues of pesticides and it has been found that with the ageing of residues or with the increase in the sampling days over treatments the effect of washing decreases to remove the toxicant to the same extent as that of samples collected immediately after spray where boiling or cooking is found to be effective. One of the possible reason for high percentage of removal of toxicant from immediately collected samples as most of the residues are present of the surface of the samples and hence it is very easy to remove by simple washing as observed by Dikshit et al (1984,86) Elkins et al (1968), Bhatia and Verma (1994) and Malik et al (1998). With the time elapsed the residues are migrated inside the deeper tissues or strongly adhere on the rough surface of some vegetables. Moreover, the washing cannot reduce the residues to the safe level as compared to boiling.

There are some studies where all the three culinary processes proved to be inefficient to reduce the residues below the MRL value. According to Jacob and Verma (1991) residues of quinalphos in the treated cauliflower crop would be reduced only to some extent by various home processing methods like washing and cooking. Nagesh and Verma (1997) opined that the inefficiency of the home processes for decontaminating the treated cabbage might be due to the strong adsorption properties of quinalphos and chlorpyriphos.

Effect of household preparation for decontamination of pesticide multiresidues in fruits and vegetables

Low levels of pesticide residues were detected in 97(40%) of mt 243 samples analyzed after following normal household washing, peeling and cooking procedures. The number of samples containing detectable residues dropped to 47(19%) after household preparation. These results indicate that residue level in most commodities are substantially reduced after household preparation (Schattenberg et al., 1996)

Ramesh and Balasubramanian (1999) performed a study with fruits and vegetables collected from Chennai local markets and fortified with known concentrations of various pesticides followed by decontamination study with different household preparations like washing, cooking , peeling resulting 65-95% decontamination of pesticide residues at different stages of 512 raw market samples analyzed, the organochlorine and organophosphorus pesticides present in the 12 samples were removed resulting in residues well below the toxicologically acceptable limits.

A short rinse in tap water reduces pesticide residues on many types of produce (Krol et al., 2000). Rinsing removed residues for nine of the twelve pesticides studied. Among captan, chlorothalonil, iprodione, vinclozolin, endosulfan, permethrin, methoxichlor, malathion, diazinon, chlorpyriphos, bifenthrin and DDE; residues of vinclozolin, bifenthrin and chlorpyriphos were not removed. This study confirms that the water solubility of pesticides does not play a significant role in the observed decrease. The majority of pesticide residues appear to reside on the surface of produce where it is removed by the mechanical action of rinsing.

Earlier studies of the effects of commercial and home preparation on pesticide residue in fruits and vegetables were summarized by Zabik (1987). The early studies showed residue reduction to be substantial, with percentage reduction of chlorinated hydrocarbons ranking from 50 to 99+ % for commercial preparation and from 14 to 99+ % for home preparation with the exception of parathion in spinach and broccoli, commercvial and home prewparation substantially reduced organophosphate residues, with the reduction generally being in the high 80 or 90% range. Carbamate residues were reduced by 58 to 99+ % when the vegetables were commercially processed but only by 11 to 92% in home preparation.

A recent study in Korea supports these earlier studies (Lee and Lee, 1997). These authors found that 45% of the organophosphate residues were eliminated when the foods were washed in water, 56% with detergent washing, 91% with peeling, and 51% with blanching or boiling.

Methods of multiresidue analysis of pesticides in fruits and vegetables

Analysis by gas chromatography

Nakamura et al (1994) developed a method for multiresidue analysis of 48 pesticides (20 organophosphorus, 7 organochlorine, 14 organonitrogen and 7 pyrethroid pesticides ) permitted in Japan on the basis of capillary GC after extracting the pesticides with nacetone from vegetable and fruit samples or with acetonitrile from lipid containing crops followed by reextraction into ethyl acetate (test solution). Organophosphorus pesticides were directly determined by GC-FPD. Organonitrogen pesticides were determined by GC-FTD (GC-NPD) following clean up by silica gel chromatography. Organochlorine and pyrethroid pesticides were measured by GC-ECD after clean up by florisil column chromatography. Recoveries for ten crops at fortification levels of 0.05-0.25 ppm were 42.5-128.5%. the detection limits were 0.001 ppm for organophosphorus and organochlorine pesticides and 0.01 ppm for organonitrogen and pyrethroid pesticides.

A multiresidue method was used by Dejonckheere et al (1996) for determination of organochlorine, organophosphorus and organonitrogen pesticides in vegetables and fruits which were extracted with acetone followed by liquid-liquid partitioning with water:apolar pesticides in petroleum ether phase, polar pesticides extracted from aqueous layer with dichloromethane and analyzed by gas chromatography with electron capture (GC-ECD), flame photometric (GC-FPD) and thermoionic specific (GC-TSD) detection.

The method used for multiresidue determination of 52 pesticides including organophosphorus, organochlorine, organonitrogen, certain pyrethroids and dithiocarbamate pesticides in vegetables and fruits was described by Dogheim et al (1999) utilizing gas chromatography. Samples were extracted with acetone followed by partitioning with hexane and dichloromethane and estimated by GC-ECD and GC-NPD. Dithiocarbamates were digested in mixture of concentrated HCl, SnCl2 and water for evolution of CS2 which is collected in an ethanolic solution of copper acetate and diethanolamine to form a yellow complex. The absorbance of yellow product was determined spectrophotometrically at 435 nm. The average recoveries and CVs of the 52 pesticides were 72-118 and 1-20%, respectively at the spiking levels of 0.01-1 ppm. A similar kind of method was also described by Kole et al (1998).

Krol et al (2000) used a multiresidue procedure for determination of 12 pesticides in vegetables where samples were extracted with 2 propanol and petroleum ether followed by washing with distilled water 3 times. Final analysis of the samples was performed by GC-ECD, FPD, XSD and/or ELCD.

Ramesah and Balasubramanian (1999) described a method to determine organochlorine, organonitrogen and organophosphorus pesticides in vegetables and fruits following extraction with 2-propanol and petroleum ether by mechanical shaker followed by partitioning with distilled water and column cleanup over florisil for OC and OP pesticides. For organonitrogen pesticides the extraction was done with acetone followed by partitioning with 10%NaCl and ethyl acetate and column clean up over silica gel. organochlorine, organophosphorus and organonitrogen compounds were analyzed by GC-ECD,GC-FPD and GC-NPD, respectively.

Using GC-ECD, the efficiencies of acetonitrile and acetone to extract the 8 pyrethroids from 6 fruits and vegetable samples were compared by Pang et al (1997). The extraction efficiency of acetone was competitive with that of acetonitrile for the 6 fruit and vegetable samples. The ruggedness tests demonstrated further that the proposed method is simple, accurate with good precision and suitable for multiresidue analysis of pyrethroid in various agricultural products.

Organophosphorus and organochlorine pesticide residues from fruit and vegetables by capillary GC with electron capture detector (ECD), nitrogen phosphorus detector (NPD), flame photometric detector (FPD) in the sulfur and phosphorus modes, and mass spectrometry detector (MSD) in selected ion monitoring (SIM) mode were determined by Torres et al (1995) following extraction by Matrix Solid Phase Dispersion (MSPD) resulting recoveries of 41-108% with relative SD of 2-14% in the conc. range 0.5-10 µg/liter in oranges, lemons, grapefruit, pears, plums, lettuces and tomatoes.

A multiresidue method as described by Sannino et al (1995) for quantitative determination of 39 organophosphorus compounds (parent pesticides and their major metabolites) in 7 fatty processed foods based on automated gel permeation chromatography with a Biobeads SX3 column and a methylene chloride-cyclohexane (15 + 85) eluant after extraction with methylene chloride. Organophosphorus compounds are quantitated by GC-FPD using OV-1701 and DB-5 columns. Average recoveries from samples fortified at 0.025-1 mg/kg ranged from 50.6% for dichlorvos to 185% for malaoxon. Determination limits were between 0.005 and 0.040 mug/mL. Results were confirmed by gas chromatography/mass spectrometry with selected-ion monitoring.

Gas chromatographic conditions for separation and identification of the compounds were selected using two capillary columns of different polarities and two detectors, ECD and NPD for multiresidue quantitative determination of 37 pesticides in fruit and vegetables and to study the efficiency of gel-permeation chromatography clean-up after ethyl acetate extraction (Balinova,1999).

Trova et al (1999) performed liquid chromatographic determination of pesticide residues (including azinphos-ethyl, azinphos-methyl, carbaryl, diflubenzuron, dinocap and teflubenzuron) in vegetables after extraction using an ethyl acetate/n-hexane solvent system instead of the widely employed methylene chloride. Recoveries as required by ‘Guidelines for residues monitoring in the European Union’ were observed; the new solvent system may be considered as an alternative to halogenated compounds, dangerous for their toxicity and harmful for their environmental behaviors, in extraction of HPLC-determinable active compounds.

A wide range screening method was proposed by Gelsomino et al (1997) for multiresidue analysis of 77 pesticides (12 organohalogens, 45 organonitrogens, 11 organophosphorus and 9 pyrethroids) in agricultural products using gas chromatography equipped with long, narrow-bore fused-silica open-tubular columns and electron-capture detector (ECD). Residues were extracted with acetone followed by dichloromethane partitioning and gel permeation chromatographic clean up. Recoveries of the majority of pesticides from spiked samples of carrot, melon and tomato at fortification levels of 0.04-0.10 mg/kg were 70-108%. Limits of detection were less than 0.01 mg/kg for ECD.

Beena et al (2002, 2003) carried out monitoring of vegetable samples adopting a multiresidue analytical technique employing GC-ECD and GC-NPD systems with capillary columns.

Ueno et al (2003) studied an efficient and reliable multiresidue method for determining 52 nitrogen- and/or phosphorus- containing pesticide residues in a large number of vegetable samples in which samples were extracted with acetonitrile, and the separated acetonitrile layer was purified by gel permeation chromatography that divided the pesticide eluate into 2 fractoions, the pesticide fractions were respectively purified by a 2-step minicolumn cleanup, the second fraction through silica gel minicolumn; first fraction through the tandem minicolumn (florisil minicolumn, inserted on silica gel minicolumn) which was eluted with acetone-petroleum ether (3+7). The combined eluate was subjected to dual column gas chromatography with nitrogen-phosphorus and flame photometric detection. Recoveries of 52 pesticides from fortified samples ranged from 72 to 108% with relative standard deviations of 2-17%, except for the recoveries of methamidophos and chorothalonil. The detection limits of the pesticides were satisfactory (0.001-0.009 mg/kg) for monitoring of pesticide residues in vegetables.

Menkissoglu et al (2004) performed a study of the matrix induced effect for 16 common pesticides, most frequently found in monitoring studies in tomato pepper and cucumber, using a simple multiresidue method with GC-ECD or NPD, without a previous cleanup step. Anomalously high GC responses and subsequently very high recoveries for several pesticides in the extracts were obtained by a conventional calibration with pesticide solution in ethyl acetate.

A faster, less effective, environmentally safer supercritical fluid extraction (SFE) method was evaluated by Garcia et al (1996) over conventional sonvent extraction methods for the extraction of imidacloprid, methiocarb, chlorpyrifos, chlorothalonil, endosulfan-1, endosulfan-2 and endosulfan sulfate, from pepper and tomato using vegetable sample: anhydrous magnesium sulfate (5:7) mixtures to carryout the extraction with supercritical CO2 and HPLC/DAD,GC/ECD and GC/FPD for analysis. The chosen SFE conditions were 300 atm, 500C, 200?l of methanol static modifier, 1 minute static time, and dynamic extraction with 15 ml of CO2 and collection in 3 ml of ethyl acetate. Except for imidacloprid, which was not recovered under any of the assessed conditions, pesticide recoveries were greater than 80%.

A simplified method is described by Chaput (1987) where reverse phase liquid chromatography was utilized with post column derivatisation and fluorescence detector to determine 7 N-methyl carbamates (aldicarb, carbaryl, carbofuran, methiocarb, methomyl, oxamyl and propoxur) and 3 related metabolites in fruits and vegetables after extraction of the sample with methanol followed by gel permeation chromatography (GPC) or GPC with on-line Nuclear-celite clean up for crops with high chlorophyll and/or carotene content (e.g. cabbage and broccoli). Recovery data were obtained by fortifying 5 different crops (apples, broccoli, cabbage, cauliflower and potatoes) at 0.05 and 0.5 ppm. Recoveries averaged 93% at both fortification levels. The coefficient of variation of the method at both levels is

Abhishek Agarwal asked:


I’ve been gardening vegetables for quite a while now, and I’ve learned some lessons the hard way. Vegetable gardening offers some great rewards - the pride and satisfaction of cultivating beautiful edible plants and the savings on the weekly grocery bill! Here are some tips that should help you plan and grow healthy fresh vegetables in your vegetable garden.

The Versatile Legume

There are two basic types of beans - bush beans and pole beans. Bush beans do not need support, and pole beans are climbers. In my garden, I normally grow bush beans because they require less work. Call me lazy. Call me well-fed.

But I’ve found that pole beans are best in my vegetable garden are nice because they can climb along old fences or up the stalks of taller plants like sunflowers. I’ve also used pole beans to beautify my vegetable garden. I’ve planted these tall bean plants at the end of each row of the vegetable garden, making arches from tree limbs bound to make arches from row to row. The pole beans grow along the branches, making an attractive frame for the vegetable garden.

Beans are a warm-season crop and are easy to grow. They like rich, warm, sandy soil. They need full sun and well-drained soil. Also, I’ve found that they grow better when I rotate them with other vegetables every other growing season.

For the best tasting beans, I wait until all danger of frost has passed and dig the vegetable garden deep. Normally, I work the garden several weeks before I plant the beans because birds will eat the insect eggs and larvae that might damage my plants later. Then I work some lime into the soil to give the beans a healthy start.

I plant my bush beans from one to 1-1/2 inches in the surface and about eighteen inches apart. My pole beans need more space with rows three feet apart for best results. Bush limas need more space than most dwarf bean plants - as much as pole beans. Remember to plant the beans edgewise with the eye pointed down.

Generous spacing allows for easy cultivation with a hoe through the growing season. And if my bean plants get to high, I just pinch off the ends of the growing plants. This encourages outward, rather than upward, growth.

Bush beans include dwarf, snap or string, wax, limas, and what is called brittle beans. Pole beans include pole limas, wax, and scarlet runner. The scarlet runner is a wonderful decorative addition to my vegetable garden. Its flowers are deep red and look great against my old fence. Scarlet runners are nice additions to flower gardens and anywhere you want a vine. The nicest thing about the scarlet runner is that you get both beauty and food.

You Can’t Beat Beets!

Beets are root vegetables that grow on flowering plants. They’re easy to grow, and you can eat almost all of the plant. The top leafy part (a good source of Vitamin A) can be used fresh in salads, and the roots (good source of Vitamin C) can be cooked. Believe it or not, the leafy green part is more nutritious than the root!

While beets tolerate heat, they do best in a cooler climate. They’re good for a long growing season, and you can stagger planting to assure a continuous supply of fresh beets throughout the rest of the year.

Beets need organic soil to grow well. My beets do best in rich, sandy loam. I learned the hard way that fresh manure is fatal for beets. A particle of manure next to a beet root can doom a young plant. To avoid this, I dig a foot-deep trench, spread a very thin layer of manure at the bottom of the trench, and cover the manure with well-crumbled top soil. That way, you get the fertilizer benefits of the manure while also protecting your young beet plants.

When planting, I space rows about one foot apart to leave enough room for cultivation of my vegetable garden. Beet “seeds” are really clusters of small seeds in a dried fruit. They won’t grow well if they’re transplanted, and they need to be handled more carefully than many other vegetables. I plant the seeds about one-half inch deep in the rows. I’ve also found that I have to thin my beet sprouts to keep them healthy. Beets have very shallow roots, so I have to weed the vegetable garden often so that they don’t have to compete with weeds for important nutrients.

The Diverse Cabbage Family

The Crucifer family - cabbages - include many vegetable plants: cabbages, cauliflower, broccoli, kale, brussel sprouts, and kohlrabi (a combined cabbage-turnip).

The high-classed cauliflower needs rich soil and doesn’t tolerate frost. I’ve learned to give my cauliflower plenty of manure water for extra richness. Like with young cabbage, the outer leaves should be well- bent to get a healthy white head. I’ve found it best to plant and easier to grow the dwarf varieties.

Kale is not so picky. Though it needs rich soil like cauliflower, it can tolerate frost. Because kale matures slowly, it needs to be planted in early spring. But you can also plant it in early fall to get an early crop the following year.

The popular brussel sprout is a good substitute for the larger common cabbage plant. I enjoy growing brussel sprouts in my vegetable garden because their stalk stands tall. Almost like an umbrella, the top is a closed head of leaves. But this is not the part we eat. The umbrella crown shades the delicious small cabbages (sprouts) that grow along the stalk.

Like most Crucifer plants, brussel sprouts need rich soil and lots of water. I plant the seeds in May and then transplant the young plants in late July. My vegetable garden rows for brussel sprouts are 1-1/2 inches apart, and I put the plants about a foot apart in the garden rows.

Kohlrabi bridges the gap between cabbage and turnips. Sometimes called the turnip-root cabbage, its stem expands into a turnip-like vegetable. The true turnip swell is underground, but the kohlrabi’s edible part is above ground. Kohlrabi is easy to grow, but I have to encourage the plants to grow fast. Growing too slowly, the swell gets too woody for good eating.

I like to plant the seeds inside in early spring and then transplant them to my vegetable garden as the weather and soil get warmer. I form my vegetable garden rows two feet apart, and put the young plants about a foot apart when I transplant them to the outdoors. Kohlrabi seeds go a long way - an ounce of seed will produce a hundred-foot row of plants. A great early crop, I prepare and serve my kohlrabi like I do with turnips.

One of my favorite cabbage plants is the Savoy. It’s one of the best varieties for cooking, especially for slaw and salads, and it’s best for growing in poor soils. I plant seeds early in the year (February) under cover and then transplant the young plants to my vegetable garden in the spring (March or April). The closer together I plant the young savoy, the smaller their heads. So I try to provide for at least one foot of space in all directions around each young plant.

What’s Up, Doc, with Carrots?

Carrot is a hardy cool-weather plant that creates a thick root in its first growing season. There are two general types of carrot plant: long roots and short roots. For healthy long-root types, I have to work the soil down to at least eighteen inches. The short carrots do well in eight inches of sandy soil. Like beets, carrots don’t tolerate manure very well.

I’ve also found that I must thin carrots frequently. As the seedlings sprout, they are too close together and compete for nutrients and sunlight. I thin a little, wait a while, and then thin again. I love growing carrots because I can harvest the young tiny carrots for my table. I can also wait and have big Bugs Bunny type carrots for my kids.

Cucumbers - the Fresh Pickle

Cucumbers are really fruit, but they can be grouped with gourds among vegetables. I’ve heard the cucumber originated in India. It’s a creeping vine that roots and grows in spiraling strands or climbs trellises or other supports. Its large leaves shade the fruits.

I get the best plants when I use light, sandy, organic soil. And I’ve also found it’s best to plant them on a slope where drainage is easiest. In hot-houses, they can hang from the ceiling where they become beautiful hanging vines. I’ve seen some brave vegetable gardeners keep a hive of bees in their hot-houses to help with cross-fertilization of their cucumber plants.

I’ve found that it’s best to plant the seeds indoors, covered with one inch of rich soil. In an area of about 30 square inches, I plant six seeds with the germinating end down. When all frosts are past, I plant each set of six plants, together with the original planting soil, in the open vegetable garden. Later, I plant them in hand-made hills with four feet of space on all sides.

Let Us Have Lettuce

Lettuce is one of the earliest human vegetable crops, growing wild before it was cultivated by man. I can tuck it into spaces throughout my vegetable garden. It’s a very decorative plant, with a compact head and lovely big green leaves.

As the lettuce plants age, they go to seed. I pull them up, as I have no interest in going into the seed business. But I do want fresh tender lettuce throughout the season. The only way I have achieved this is by planting in early spring and then planting again every ten days or so throughout the summer.

There are many varieties of lettuce with different planting and growing requirements. I prefer leaf, cos, and butterhead lettuce because I can plant them anytime in the early spring. I’ve found that my lettuce doesn’t do well in the heat, so I stop planting about a month before the hottest part of the summer. But I’ve planted lettuce plants in the shade of other plants in my vegetable garden and planted late in the summer to get good fresh lettuce into the fall.

I plant lettuce seeds shallow - from a quarter to half an inch deep - in rows about a foot apart. Then I thin the seedlings so that plants have six to eight inches between them. The nice thing is that I can serve the seedlings I’ve thinned in my early spring salads. Nothing goes to waste.

More than Veges in My Vegetable Garden - Melons

Though they originated in Asia and parts of Africa, melons pleased the taste of ancient Romans. They’re a summer fruit, often grown in hot-houses. They need a lot of space, a lot of heat, and a lot of sun. They also need 3-4 months of growing time, fertile soil, and lots of water.

I prepare 2-3 foot mounds spaced 4-6 feet apart for my melon plants. The mound soil should be compost-rich. Sprinkling sand or lime on and around the mounds helps prevent insect damage to the young plants.

As they grow, the vines get to heavy to stand on their own, so I provide something like tennis netting for the vines to follow. I plant eight seeds in a mound, setting them about two inches apart, and planting them about an inch deep. Watermelon plants need more space - up to ten feet between each mound.

When the plants reach about four inches in height, I reduce the number to two per mound, always picking the sturdiest plants. I cut the close to or below the surface rather than pulling plants up as this is likely to damage the roots of the remaining plants.

One word of advice - be very careful in watering your melons. They’re vulnerable to fungal diseases, and overhead watering may be dangerous for them. I’ve found that drip-irrigation, a slow trickle at the base of the plant, keeps my melons growing healthy throughout the growing season.

The Joys of Vegetable Gardening

I love my vegetable garden. It gives me many hours of peace and serenity as I work with the soil and gently grow beautiful plants. My vegetable garden repays my family with many fresh, healthy meals and good nutrition.

It’s taken a lot of experimentation and some failures to have a productive vegetable garden, but it’s been worth every minute of work. The joy of handling soil and seed, tending to precious young plants, and harvesting beautiful mature plants is one of the most satisfying things I’ve ever done.