Genetically modified food (GMF) refers to the food in which foreign genes (not of the same species) are embedded into the genome of a species through genetic engineering (transgenic) technology, including transgenic plant food, transgenic animal food and transgenic microbial food. As a new biotechnology, the immaturity and uncertainty of transgenic technology inevitably make the safety of genetically modified food become the focus of attention. Spanish: Alimento transéNico, the world's earliest genetically modified crop 1983, was born in the genetically modified food of Monsanto company in the United States.
In order to improve the nutritional value of agricultural products and produce food more quickly and efficiently, scientists use genetically modified foods.
The method of gene changes the genetic information of organisms, assembles new genes, and makes future crops with high nutrition, storage resistance, pest resistance and herbicide resistance, and constantly produces new genetically modified foods.
Genetically modified food has many advantages: it can increase the yield per unit area of crops; The production cost can be reduced; Transgenic technology can enhance the ability of crops to resist pests and viruses; Improve the storage resistance of agricultural products, extend the shelf life, and meet people's demand for genetically modified food-potatoes.
The growing demand for living standards; Can greatly shorten the time of crop development; Can get rid of the influence of seasons and climate, and supply at low prices in four seasons; Breaking species boundaries, constantly cultivating new species and producing food beneficial to human health. Genetically modified food also has disadvantages: the so-called increase in production is achieved without environmental impact, and if it encounters natural disasters such as rain and snow, it may reduce production even more. Many studies have shown that genetically modified foods are harmful to the immune function of mammals. More research shows that experimental hamsters will be extinct in the third generation after eating genetically modified food.
Toxicity problem
Some researchers believe that artificial extraction and addition of genes may not only achieve some expected effects, but also increase and accumulate trace toxins in food.
anaphylactic reaction
People who are allergic to a food are sometimes allergic to a food that was not allergic before, which is more hidden than genetically modified food.
For example, scientists added a certain gene of corn to the genes of walnuts, wheat and shellfish, and protein also added it along with this gene, so people who were allergic to corn before may be allergic to these walnuts, wheat and shellfish.
Nutrition problem
Scientists believe that foreign genes will destroy the nutrients in food in a way that people still don't understand.
Resistance to antibiotics
When scientists add a foreign gene to plants or bacteria, this gene will be connected with other genes. After people take this improved food, the food will transfer the drug resistance gene to the pathogenic bacteria in the human body, which will make the human body resistant to drugs.
Threaten the environment
Many transgenic varieties contain bacterial genes extracted from Bacillus, which can produce a protein that is toxic to insects and pests. In a laboratory study, the larva of a butterfly died or developed abnormally after eating the pollen of milkweed plants containing Bacillus genes, which caused another concern of ecologists. Other species that are not within the scope of improvement may become victims of improved species. Finally, biologists worry that in order to cultivate some better characteristics, such as stronger resistance to pests and diseases and drought, the characteristics of crops are likely to be spread to wild species through pollen and other media.
In China, China's international level in biotechnology and genetic modification is not low. Apart from the United States, Japan, Germany and some developed countries in Europe, China may be second to none among developing countries and has reached the international advanced level in some aspects. In China, more than 50 kinds of plants, including food crops, are researching and developing transgenic plants, as well as animals and fish. From 1997 to 200 1 the end of the year, the Ministry of Agriculture accepted 587 applications for environmental release and commercial production. Finally, 4 15 items were approved for environmental protection release. Although environmental discharge can be planted, it is only allowed to be planted in a small area, and isolation measures should be taken. There are 46 items approved for commercial production. Commercial production has no isolation measures and can be planted at will, mainly 6 kinds. One is cotton. It is insect-resistant, transgenic Bt cotton; There are tomatoes, tomatoes resistant to cucumber mosaic virus, and a late-maturing tomato; It is also a sweet pepper resistant to cucumber mosaic virus Petunia; There are also some animal feed additives and microbial agricultural products. At present, in our China market, there may be a small amount of truly domestic transgenic tomatoes planted in Hubei or Guangdong, which is said to be no more than 1 10,000 mu. Sweet pepper may be limited to Liaoning. One thing is that commercial production is very limited, because it may not pass the seed approval. The main genetically modified product is cotton, which can neither be eaten nor eaten, but its seeds can be used to extract oil. We did a survey. Many farmers in Hebei Province use cottonseed to extract oil, which is also food, so they eat genetically modified cotton oil. The seed area of transgenic cotton is relatively large. From 1996 to 200 1 year, more than 30% of cotton planting area is genetically modified, and 70% of genetically modified cotton is seeds provided by Monsanto. There are still 30% transgenic cotton varieties cultivated by our domestic research institutes, the Cotton Institute of China Academy of Agricultural Sciences and many provincial agricultural academies, and the amount of 30% is still quite large. Therefore, China has become one of the four countries that plant genetically modified organisms in the world, mainly because the weight of genetically modified cotton is relatively large. There are not many genetically modified foods on the market in China, and there is nothing produced by ourselves, but not everyone has never eaten them. In fact, we basically don't leave with genetically modified food every day. The main reason is that we have imported genetically modified foods and more genetically modified soybeans. Genetically modified soybeans are squeezed into oil and made into bean products. We can't escape and eat them. For example, among the 200 1 imported13.94 million tons of soybeans, the United States has 5.72 million tons and Argentina has 5.02 million tons, mainly from these two countries. At that time, 63% of soybeans in the United States were genetically modified, and more than 90% in Argentina were genetically modified, so most of these imported soybeans were actually genetically modified. In 2002, after the promulgation of China the State Council regulations, there were some changes in 2002 compared with 200 1. Our soybean imports from Brazil increased by 23.7%, Brazil is basically non-genetically modified, soybeans imported from the United States decreased by 19%, soybeans imported from Argentina decreased by 44.7%, and overall imports decreased by 18.7%. Why did China import genetically modified soybeans? Now that China has joined the WTO and the international economy is globalized, he will buy whatever is cheap and superior. Our northeast soybeans are on the market, and so are American soybeans. In the past, the price of northeast soybeans was 20% higher than that of American soybeans, but the oil content of our soybeans was not as good as that of American soybeans. The oil content of American soybeans reaches 2 1%, and we only have 18%, so the oil mill uses American soybeans with high oil yield. However, this situation has changed a little now. The Ministry of Agriculture has been promoting high-oil soybeans in the past two years, and our oil content has reached 2 1%. Moreover, our own soybeans are all non-GM soybeans, and now Japanese and Koreans have to eat non-GM soybeans. Our soybeans are called organic soybeans or non-GMO soybeans, and now our soybean exports have increased. Dalian Soybean Futures Exchange used to trade genetically modified soybeans in the United States, but now it trades non-genetically modified soybeans in China.
Yuan Longping said that genetically modified foods cannot be generalized. When promoting transgenic varieties resistant to pests and diseases, we should be cautious about all kinds of questions raised by all sectors of society about genetically modified foods. On March 3rd, Yuan Longping, a member of the Chinese People's Political Consultative Conference (CPPCC) and the "father of hybrid rice", said in an interview that genetically modified foods cannot be generalized, and it is necessary to be cautious in promoting genetically modified varieties resistant to pests and diseases. "Genetically modified foods cannot be completely rejected or completely accepted. Some of them do not have security problems, but some of them need further in-depth study of their security. " Yuan Longping said that through transgenic technology, people can obtain better varieties with good quality, high yield, rich nutrition and strong resistance to pests and diseases, but it may also cause biological genetic pollution. "For example, the toxic protein gene is very effective in preventing insects, but people are worried about human health. Yuan believes that it is safe for two generations to eat genetically modified food.
It may also have adverse effects. Yuan Longping said that this is reasonable and the country is also very cautious on this issue. So far, the transgenic varieties resistant to pests and diseases have not been put into the production market and are still in the experimental stage. "But we can't kill genetically modified foods with a stick, thinking that genetically modified foods are bad, and some genetically modified foods are not toxic. We can't think they all have problems. " Yuan Longping introduced that rice and wheat belong to C3 plants, while corn and sugarcane belong to C4 plants. The photosynthetic efficiency of the latter is 30%-50% higher than that of the former. Now, they have transferred C4 gene from corn to rice to improve its photosynthetic efficiency. "I don't think there are food safety problems for such genetically modified varieties." Yuan Longping said that using biotechnology to develop crop breeding is the future development direction and inevitable trend, and transgenic technology is a molecular technology, so it is necessary to strengthen the research and application of transgenic technology. We should take a scientific and prudent attitude towards genetically modified foods, especially directly edible genetically modified varieties, but we can't simply refuse them. He said that due to the potential risks of genetically modified foods and the uncertain ways of gene pollution, proliferation, diffusion and removal, once the genetically modified organisms have problems, they can't be controlled at all, and no one can bear the responsibility. "Whether genetically modified foods are harmful to the human body will take a long time to investigate, and it will take at least two generations to reach a conclusion." Yuan Longping admits that the public's concern about the safety of genetically modified crops is mainly due to the fact that some genetically modified crops, especially those resistant to pests and diseases, have their genes derived from a toxic protein in a bacterium. Because insects will be poisoned if they eat poisonous protein, it is hard to say whether long-term intake of this substance is harmful to people. "Now the experiment can't let people do, all through the mouse. However, a person is a person and a mouse is a mouse, which has no harm to the mouse, but it is not necessarily harmless to people. People and people's bodies are different. We should be cautious about some genetically modified foods that are resistant to diseases and insects and make a systematic safety assessment. " If transgenic rice resistant to pests and diseases is to be tested on human body, I will be the first to sign up. "Yuan Longping said that as long as there is no problem for two generations, this genetically modified food is safe.
The developed transgenic tomato 1994, which can prolong maturity and keep fresh, was approved for marketing in the United States. The research and development of genetically modified food has developed rapidly, and the variety and output of products have also increased exponentially, and the problems related to genetically modified food have become increasingly prominent. In fact, the basic principle of transgene is not difficult to understand, which is similar to conventional cross breeding. Hybridization is to transfer the whole gene chain (chromosome), and transgene is to select the most useful short gene transfer. Therefore, transgene has higher selectivity than hybridization. That is, one or more foreign genes are transferred into an organism (animals, plants and microorganisms) by means of genetic engineering, and the corresponding products (peptides or protein) are effectively expressed, so that the organism can be used as food or food processed from it.