Detection of pesticide residues in fruits and vegetables

With the continuous progress of cultivation technology, the growth period of vegetables has become shorter and shorter, and with the intensification of environmental pollution, the diseases and pests of vegetables are also becoming heavier and heavier. Most vegetables need to be sprayed multiple times in a row before they can mature and go on the market. Leafy vegetables with heavier pesticide pollution, among which chives and rapeseed suffer the largest proportion of pollution. Eggplants, fruit vegetables such as green peppers, tomatoes, etc., tender pod vegetables such as beans, etc., bulb vegetables such as scallions, garlic, onions, etc., the pollution of pesticides is relatively small, but some are relatively large.

The main pesticides used in vegetable production are as follows: First, organophosphorus pesticides. The pesticide is a broad-spectrum insecticide, which is widely used. There are mainly more than 60 kinds of diethyl, trichlorfon, dichlorvos, endophosphorus, parathion, malathion, etc. Organophosphorus is unstable, volatile, and easy to decompose in the natural environment. It is easily decomposed by enzymes when it enters the living body. Therefore, it does not pollute the environment and has a short residual time in food. Therefore, there are few chronic poisonings and more acute poisonings. Organophosphorus is a nerve poison. People who eat fruits and vegetables or tea leaves, potatoes, grains, etc. that are applied with organophosphorus pesticides may experience symptoms such as muscle tremors, spasms, elevated blood pressure, rapid heartbeat, and even coma and death. Second, organo The pesticide is highly toxic pesticides, among which 666, DDT and other pesticides have long been banned in our country, but there are still cases of illegal use, especially lindane, 7O54, toxaphene, chlordane, etc. continue to be used. Organic chlorine has strong fat solubility, is not easy to hydrolyze and degrade, is very stable, accumulates in human body fat, and can remain in nature and food for a long time. After stopping use, naturally, the environment will take 25 to 110 years to recover. Food contamination with organic chlorine often starts from the ingestion of plankton in water bodies. Fish and shrimp eat plankton, and eventually enter waterbirds and human bodies. Its enrichment can be increased to 8 million times. Fruits and vegetables and grains, cereals, potatoes, tea, tobacco can be, residual organic chlorine, poultry, fish, eggs, milk and other animal food pollution rate is higher than plant foods, and will not be because of its storage, processing, cooking and reduce, it is easy to enter the human body savings. Organochlorine pesticides can cause acute or chronic poisoning. Acute poisoning causes central nervous system symptoms in poisoned people. Because of its accumulation in human fat, acute toxicity is low and symptoms are light, generally fatigue, nausea, dizziness, insomnia; chronic poisoning can cause human liver, kidney and nervous system damage, DDT and carcinogenicity. Third, carbamate pesticides. This type of pesticide is a widely used new type of insecticide and herbicide, such as aphipoxil, carbofuran, carbofuran, carbofuran, carbofuran, etc. Its toxicity is similar to that of organophosphorus, but it is less toxic and recovers quickly. Eating fruits and vegetables and grains, potatoes, tea, etc. with more residues of such pesticides, the poisoned person will have roughly the same symptoms as organophosphorus poisoning, but because of its light toxicity, it can generally recover on its own in a few hours. Fourth, pyrethroid pesticides. Pyrethroid pesticides mainly include cypermethrin (decantol), cypermethrin (enemy-killed), and fungicidal fat (quick-killed pyrethroid). They are low-toxic to humans, but they are accumulative. The symptoms of poisoning are nervous system symptoms and skin irritation symptoms. In order to prevent the harm of pesticide residues, the following points should usually be paid attention to: 1. Try to buy fruits and vegetables in a regular market with hygiene supervision, and the product packaging has one of the four signs of "quality and safety", "pollution-free products", "green food", and "organic food". Relatively speaking, it is safer and more reliable. 2. Buy fruits and vegetables seasonally, and often apply large amounts of chemical fertilizers, pesticides to ripen and go on the market in violation of the safety interval regulations. 3. Pesticide residues are related to fruit and vegetable varieties. Generally, there are more pesticide residues in leaves and stems, melons and fruits, and beans, and less in rhizomes. 4. Know the origin of fruits and vegetables as much as possible, and avoid buying fruits and vegetables grown in heavily polluted areas and on both sides of highways. 5. Fruits and vegetables should be rinsed first and then soaked, that is, the fruits and vegetables should be thoroughly cleaned and then soaked in water for 10 minutes, but do not soak for too long, so as not to return the surface pesticides to the inside of fruits and vegetables after entering the water. 6. The incision is easily contaminated by residual pesticides, so do not cut and soak vegetables first; rinse the fruits and vegetables with water several times after soaking