Good afternoon, classmates and teachers. At this time, I would like to introduce to you the safety issues of genetically modified food.
1. Genetically modified organisms, genetically modified foods and their advantages
What are genetically modified organisms? Through biotechnology and genetic engineering, scientists can isolate a certain gene from a certain organism and then implant it into another organism to change its genetic composition and make it acquire qualities and characteristics that it did not originally have. For example, Bacillus thuringiensis contains a gene that can produce a protein that is toxic to lepidopteran insects. This gene can be transplanted into cotton to make cotton produce this protein and resist cotton bollworm. Another example is a gene in Arctic fish. It has antifreeze properties, so scientists extracted it and implanted it into tomatoes, thus creating a new variety of cold-resistant tomatoes. Organisms containing genetically modified ingredients like this are called genetically modified organisms, and foods containing genetically modified organisms are called genetically modified foods.
Genetically modified foods often need to undergo strict approval before being commercialized. For example, the government regulatory agencies involved in the safety of genetically modified organisms in the United States include the Food and Drug Administration, the Department of Agriculture, and the Environmental Protection Agency. Each department has a clear division of labor, forming a very efficient and strict safety assurance system. Most scientists around the world support genetically modified technology and affirm the safety of genetically modified foods. Since the United States allowed the first genetically modified food to be sold in supermarkets in 1996, more than 200 million Americans have eaten it for about 10 years, and tens of millions of Australians and Canadians have also eaten it. So far, no one has been found to prove that it is problematic. case.
Although there is currently no evidence that genetically modified food is unsafe, compared with traditional natural food, it is still a new thing, and there are indeed uncertain factors and unknown long-term effects. The safety remains to be tested in further practice. This attribute of genetically modified foods has sparked intense debate. Supporters believe it is the dawn of a new round of agricultural revolution and the second green revolution; opponents believe it is dangerous and polluting, and will cause devastating disasters to consumer safety and environmental safety.
It is precisely because of this that today’s discussion has taken place.
3. Comparative analysis of genetically modified foods and traditional foods
Genetically modified foods are the product of modern biotechnology. It refers to the use of modern molecular biology technology to transfer the genes of certain organisms to other species, transform their genetic material, and transform their traits, nutritional quality, consumption quality, etc. into the goals that people need. Foods produced using genetically modified organisms as food or as raw materials are genetically modified foods. At this stage, genetically modified foods are mainly foods made from genetically modified crops (such as genetically modified tomatoes) or processed foods using genetically modified crops as raw materials (such as soy milk produced from genetically modified soybeans).
There are certain differences between genetically modified foods and traditional foods. Traditional foods are produced through natural selection or artificial cross-breeding. Although there is no substantial difference in basic principles between transgenic technology and traditional and newly developed inter-subspecies hybridization technologies. However, the genetically modified technology used to produce genetically modified food focuses on genetic manipulation at the molecular level (i.e., gene modification and transfer through recombinant DNA technology), so it is more precise, rigorous, and more controllable. People can use modern biotechnology to change the genetic traits of organisms and create new species that do not exist in nature. Such as obtaining food plants that can kill pests, food plants that are resistant to herbicides, and food plants that can produce human vaccines. Moreover, genetically modified foods can contain genes from distant species, that is, transgenic technology is used to transfer cross-species genes into genetically modified foods, which is difficult to achieve in the natural state. For example: tomatoes contain fish genes, millet contains scorpion genes, and pork contains human genes. This can only be a myth in a natural state or using traditional hybridization techniques.
4. The main characteristics of genetically modified foods
The main characteristics of genetically modified foods are as follows.
First, low cost and high output.
According to preliminary estimates, the cost of using genetically modified technology to produce genetically modified food (cost after large-scale production) is 60% to 80% of traditional products, while the output increases by 5% to 20%, and some may increase several times or even dozens of times.
Second, it has the characteristics of "resistance to grass, resistance to insects, and resistance to stress". Transgenic technology is used to transfer genes with specific properties (such as grass resistance, insect resistance, and stress resistance genes) into specific crops, so that transgenic crops have characteristics such as "grass resistance, insect resistance, and stress resistance." On the one hand, it can reduce agricultural production costs, on the other hand, it can also increase crop yields.
Third, the freshness preservation performance is enhanced. Use genetically modified technology to enhance the preservation function of food. For example, antisense RNA transgenic tomatoes use antisense DNA technology to inhibit enzyme activity to delay ripening and softening, and the storage and preservation time are extended.
5. Discussion on the safety of genetically modified foods (human health, environmental ecology)
Currently, there are many problems with genetically modified technology. First, the development time of transgenic technology and genetic engineering is short, and there are many uncertain factors and many unresolved problems. For example: the expression rate of the transferred gene is very low, gene silencing often occurs, gene expression is unstable, and the transferred gene is prone to mutation; secondly, people lack understanding of the mechanism of the transferred gene in the target organism. For example, if fish genes are transferred into tomatoes, we know very little about how the fish genes will change the mechanism of action of the entire tomato, except that the fish genes play specific functions in tomatoes; thirdly, genetic engineering The biosafety issues caused have not yet been determined. Countries have different views on this, and scholars and the public also have divergent opinions.
Until now, genetically modified foods have not undergone long-term safety assessment before being launched on the market. There are still doubts about whether they are safe for human consumption in the long term, and the scientific community has no complete knowledge on whether these foods are safe.
International authoritative organizations such as the Food and Agriculture Organization of the United Nations, the World Health Organization and the Economic Cooperation Organization have stated that artificial transplantation of foreign genes may have "unintended consequences" on organisms. That is to say, we still do not have enough scientific methods to assess the risks of genetically modified organisms and food.
Consumers International (members include 250 consumer organizations in 115 countries around the world) stated that "no government or United Nations organization will claim that genetically modified foods are completely safe."
Genetically modified animals and plants are artificial organisms, not original species in nature. They are all alien species to the earth's ecosystem. Since genetically modified organisms also have the ability to reproduce and mate with close relatives, once they are released into the environment (for example, planted in farmland), the consequences are unpredictable, and if something goes wrong, it is difficult to remedy it. On the other hand, the impact of long-term consumption of genetically modified foods on humans is still unknown.
Are organisms modified by genetically modified technology safe? Will they cause harm to other organisms, especially humans? There are currently divergent opinions on the safety of genetically modified organisms. Questions mainly focus on whether the large-scale planting of genetically modified crops will destroy the ecological balance and whether genetically modified crops and their processed products are harmful to human health as food. The debate surrounding the safety of genetically modified crops and genetically modified foods can be summarized in the following aspects: ① Is "substantial equivalence" as a principle for testing genetically modified foods appropriate? The principle of substantial equivalence is currently an internationally accepted standard for safety assessment of genetically modified foods. It is a principle proposed by the United States or OECD countries in 1993. That is to say, whether a genetically modified organism is safe depends on whether it is safe with traditional food. Differences and comparisons between non-GMO products. If the ingredients of the food are basically the same as traditional foods, it is considered safe. However, many experts question this principle and believe that it is necessary to evaluate not only the main nutrients, but also all macro and micro nutrients, anti-nutrients, plant endotoxins, secondary metabolites and allergens. Only after the basic concentration has been analyzed can we say whether it is safe or unsafe. The principle of substantial equivalence is still questionable.
②Are antibiotic resistance marker genes dangerous? ③ Are there any allergens in genetically modified foods? Are allergens tested when declaring genetically modified foods? ④Do genetically modified foods contain toxins? ⑤What are the long-term effects of ingesting genetically modified foods to the human body? ⑥ Should genetically modified foods be labeled? ⑦ Will herbicide resistance create super weeds? ⑧Will genetically modified crops threaten biodiversity? Will it damage the environment? It seems that the safety issues of genetically modified foods mainly include two aspects: environmental safety and human health safety.
There are two schools of thought on the safety of genetically modified crops/foods. Those who support the development of genetically modified crops/foods believe that genetically modified crops/foods are safe (of course, nothing can be absolutely safe). Their reasons are: ① Since genetically modified food entered the market, no case of harming human health has been found, so it will not harm human health; ② Promoting the planting of genetically modified crops can reduce the use of pesticides, insecticides, and chemical fertilizers. Reduce environmental pollution. At the same time, the use of genetically modified technology and genetic engineering can solve many environmental problems caused by industrial production; ③ The possibility of containing allergens in genetically modified foods is extremely small, with a probability of less than 0.1%, and many traditional foods like peanuts , Shrimp can also cause allergic reactions in certain people; ④ After strict control, genetically modified foods will not contain toxins; ⑤ The principle of "substantial equivalence" is currently the best principle for testing genetically modified foods; ⑥ Genetically modified crops will not Threats to biodiversity.
The reasons for the opponents are: ① Although no case of genetically modified food being harmful to human health has been found so far, this does not mean that genetically modified food is not harmful to human health, because genetically modified food has entered people’s lives for a short time , some potential hazards will not manifest themselves in a short period of time, but will manifest themselves after a long incubation period; ② Reducing environmental pollution is not just as simple as reducing the use of pesticides, insecticides, and chemical fertilizers, but also genetically modified crops through genes Drifting or gene escape may also lead to "genetic pollution", thereby causing greater harm to the environment; ③ The cultivation of genetically modified crops will threaten biodiversity and damage the natural environment; ④ Although the content of allergens and toxins is small, if it is harmful to a certain A specific group of people may have adverse consequences; ⑤ The principle of "substantial equivalence" only focuses on results and ignores the entire process of growing genetically modified crops and the safety of the entire process of genetically modified food production, processing, transportation, and consumption; ⑥ Regarding genetically modified foods The evaluation should be a dynamic process and should not be static. Better methods need to be explored to evaluate the safety of genetically modified foods.
According to the ethical principle of non-harm, genetically modified crops/genetically modified foods cannot cause harm to the environment and human health. Otherwise, it will harm humans and nature, and will cause harm to humans and their living environment. threaten. Genetically modified crops/foods are potentially dangerous to the environment and human health. There are some examples that support this conclusion. In the "Pusztai Incident," mice eating genetically modified potatoes resulted in abnormal organ growth, reduced body weight and organ weight, and compromised immune systems. Although the report is somewhat exaggerated, it reflects to a certain extent that genetically modified foods may be potentially dangerous to human health. Because genetically modified crops and genetically modified animals are used as food or processed into food using them as raw materials, unintended changes in food ingredients cannot be ruled out, causing harm to the health of consumers. This is reflected in: whether virus-resistant crops containing virus coat protein genes will cause harm to the human body; whether insect-resistant crops contain residual anti-insect toxins; whether herbicide-resistant crops contain residual chemical components such as herbicides; whether genetically modified crops contain residual anti-insect toxins; Allergens, etc. We think these are likely to happen. The "Butterfly" case shows that genetically modified crops can harm non-target organisms, cause harm to the environment, and of course threaten biodiversity. The large-scale planting of genetically modified crops may destroy the ecological balance because it leads to "gene pollution" through "gene escape" or "gene drift". Moreover, genetic engineering and genetically modified crops may produce harmful substances, harm biological communities, and reduce biodiversity.
The use of transgenic technology to genetically modify bacteria and viruses may turn harmless or weakly pathogenic bacteria and viruses into harmful or highly pathogenic bacteria and viruses, causing harm to the survival of other animals and plants. Genetically modified plants may evolve into "super weeds", and genetically modified animals may become "monsters" or dominant organisms. The organisms generated through genetically modified technology are superior to other natural organisms in terms of traits and quality. If they are released into the environment, according to Darwin's evolutionary theory and competition mechanism of "natural selection, survival of the fittest", they will be eliminated. Wild species in the community indirectly affect the community structure through the food chain, threatening biological diversity. On July 9, 2001, the United Nations Development Program (UNDP) also admitted that genetically modified crops may disrupt the ecological balance. They may transfer their genes to related species, creating super weeds, and may also cause harm to other plants or animals. Unintended harmful effects. From the perspective of the principle of respect, human beings must not only respect themselves, but also respect nature and the laws of development of nature. Otherwise, humans will be punished by nature. Moreover, as an organic whole, genetically modified crops have their own integrity. Each nutritional characteristic and chemical structure of genetically modified crops has its own organic composition. The human body is also a very complex organic whole. Will the ingestion of new cross-species genes break this integrity? It is possible that genetically modified foods will cause adverse effects after humans consume them, and that they will disrupt the nutritional balance and physiological functions of the human body.
Moreover, as a highly dangerous alien species, genetically modified crops/foods have entered the environment, causing worrying damage to the overall ecological environment. Once the ecological integrity is broken, the consequences will be unimaginable. From the perspective of utility principles, the cultivation of genetically modified crops should be as conducive to the improvement of the ecological environment as possible. Scientifically speaking, the planting of genetically modified crops has this potential, such as reducing the use of chemical fertilizers and pesticides. However, judging from the current development of genetically modified crops, this potential for improving the ecological environment has not yet been demonstrated. On the contrary, its destructive effect on the ecological environment is increasingly exposed. Once genetically modified crops cause harm to the ecological environment, their utility to humans will be greatly reduced. Therefore, we must not only see the economic benefits brought by the commercialization of genetically modified crops/genetically modified foods, but also pay attention to its ecological and social benefits. When there is a conflict between the two, we should put ecological benefits and social benefits first, which is also an objective requirement of the sustainable development strategy. Since genetically modified crops/genetically modified foods are potentially dangerous and have safety issues, many issues require further research before conclusions can be drawn. Therefore, we must be cautious about the planting and marketing of genetically modified crops/genetically modified foods, otherwise it may endanger human health and the ecological environment, causing serious consequences. Inestimable losses or consequences.
The possible impact on ecology and environment after large-scale commercial planting of genetically modified plants. In this regard, there is a great deal of academic debate internationally. There is a genetically modified crop in Canada, herbicide-tolerant canola. This kind of rapeseed has only been cultivated for a few years, but several herbicide-resistant rapeseeds that have not been planted in the local area have been discovered. Some people call them "super weeds" and it is difficult to kill them. This fact shows that genetic drift often occurs in genetically modified foods, especially between the same species and different varieties.
Even more serious is the Mexican corn problem. Corn originated in Mexico. In order to prevent genetically modified contamination from affecting the genetic diversity of the entire corn, the Mexican government once stipulated that genetically modified corn would not be grown. However, due to various reasons, a large amount of genetically modified corn from the United States arrived in Mexico (some of it was brought in as relief supplies). Genetic contamination of corn is finally happening in some areas of the country between two states. American scientists published molecular evidence of genetic contamination in the journal Nature, where a heated debate raged among scientists. In 2002, the Mexican environmental department released a report confirming the fact of genetic contamination. In some areas, the proportion of genetic contamination in corn reached 35%.
In addition, some scientists in the laboratory used milkweed leaves, a weed with genetically modified corn pollen, to feed monarch butterfly larvae. Compared with traditional food feeding, they found that the monarch butterfly died. rate increases, or growth slows down. There are not many other examples to cite.
There are also some people who oppose genetically modified foods because they are sensitive to the phenomenon that 80% of the world's genetically modified crops are produced by five multinational companies including Monsanto and DuPont. These companies own patents on related genes, crops and seeds, and have monopoly control over the market for genetically modified products. For example, in order to achieve product exclusivity, they introduced male sterility genes or genes that required activation by specific inducers into crops, so that farmers could not save seeds or had to purchase their inducers. In order to avoid the loss of profits and the creation of import dependence caused by this technology and product monopoly, many people have joined the ranks of opponents.
When different interest groups are expressing their opinions and boasting for their own interests, when some countries with abundant agricultural products intend to block or delay the progress of this technology, those in the world who are struggling with food and clothing, and nutrition People who are suffering from bad deeds are pinning their hopes on this new technology with great potential. They believe that genetically modified foods are no more risky than traditional foods. Hunger and poverty are the biggest enemies, and survival is the primary issue. According to FAO's 6th World Food Survey, in the past 10 years, the world's grain reserves have dropped below FAO's safety limit (60 days). The population of poor countries is the majority on the planet, and their voices should not be ignored.
When we carefully identify the origins of the various voices in the debate on the safety of genetically modified foods, we cannot help but wonder again what science and technology are. Science and technology are by no means carried out in paradise. Apart from the factors of science and technology itself, the debate on the safety of genetically modified foods is essentially a manifestation of the conflict of interests between different countries and different groups. What people are arguing for is by no means a purely scientific and technological concept of "risk", but a comprehensive analysis and comprehensive measurement of its vested interests, expected benefits and expected risks. When vested interests will be damaged or the expected benefits are small, the risk is high; when the expected benefits are large, the risk can be ignored. Similarly, the security that people are arguing for is not a purely scientific and technological concept of "security", but contains the content of political security, economic security, and ethical and moral security.
Regarding genetically modified foods, we should see that there is social demand for them. It bears people's heavy expectations of alleviating hunger and poverty, and also embodies people's joyful vision of improving their quality of life and raising their living standards. This is the meaning of its existence and development. Although the current disputes between different countries and different interest groups are difficult to reconcile for the time being, we can believe that the final result is either to find a balance point that allows different interest groups around the world to reach a consensus; or it is like the development of medicine. It's the same - traditional Chinese medicine is known as Chinese medicine, and Western medicine is known as western medicine in the West. Genetically modified foods will also grow adaptively in different social environments. In any case, there is no such thing as zero risk, and nothing is absolutely safe. However, the biggest risk is to stop eating due to choking and do nothing.
6. Safety evaluation of genetically modified foods
With the continuous penetration and rapid development of genetically modified technology into the fields of agriculture, food and medicine, the safety of genetically modified foods has become one of the hot issues of global concern. one. After our country has officially become a member of the WTO, facing the large number of imported genetically modified foods, how to rationally use WTO rules to protect the health of our people, develop our country's genetically modified industry, and take the initiative in international trade is an important issue for our country's scientific and technological circles and It is a very important and urgent task facing the relevant government departments.
The core and basis for strengthening the safety management of genetically modified foods is safety evaluation. Currently, the international safety evaluation of genetically modified foods follows the principles of science-based, case-by-case analysis, substantial equivalence and gradual improvement. The main contents of the safety evaluation include toxicity, allergy, nutritional ingredients, anti-nutritional factors, marker gene transfer and undesired effects.
In science and technology plans such as "973" and "863", Chinese scientists will focus on key scientific issues such as rice and fish, such as the predictive toxicology of genetically modified foods on human health and the establishment of a serum bank for people with food allergies.
Food safety is a relative and dynamic concept. No food is 100% safe. With the advancement of science, technology and society, people have naturally put forward higher requirements for food safety. At the same time, food is not only a source of nutrition and energy, but also a symbol of culture and tradition, and a pillar of economic trade. In the 21st century, when genetically modified foods show bright prospects, it will be beneficial to our country to formulate genetically modified food industry development and safety management methods suitable for my country's national conditions based on international development trends, integrating science and technology, trade and other factors, and strengthening scientific and technological research on food safety. The healthy development of the food biotechnology industry will take the initiative in international competition in the new century.
Generally people think that traditional food is safe, but with the continuous application of new technologies in food production, food safety risks are becoming greater and greater. The essence of a considerable number of food safety risks is scientific application. risks, which can only be identified and controlled through scientific means.
Safety evaluation includes comparisons of genetically modified foods with their conventional counterparts, focusing on the determination of similarities and differences. The safety evaluation of the entire genetically modified food must consider both desired and undesired effects. If new or changed hazards, nutritional or safety issues are identified, analyzes should be conducted to determine the relationship to human health. Traditionally, new types of food plants have not been systematically and extensively evaluated chemically, toxicologically and nutritionally before being marketed (unless they are likely to be used as an essential component of the diet for special populations, such as infants). , typically strict safety evaluations are required for food additives or pesticides that may remain in food.
7. my country’s laws and regulations on genetically modified foods
In 1993, the State Science and Technology Commission promulgated the "Measures for the Safety Management of Genetic Engineering", aiming to strengthen the safety management of genetic engineering; in 1995 , the Ministry of Agriculture issued the "Implementation Measures for the Safety Management of Agricultural Biogenetic Engineering"; in 2001, the State Council issued the Ministry of Agriculture's "Regulations on the Safety Management of Agricultural Genetically Modified Organisms" to strengthen the safety management of biotechnology and genetically modified organisms; in March 2002, the Ministry of Agriculture The Ministry of Agriculture issued the "Agricultural Genetically Modified Organisms Safety Assessment and Management Measures", "Agricultural Genetically Modified Organisms Import Safety Management Measures", "Agricultural Genetically Modified Organisms Labeling Management Measures", "Agricultural Genetically Modified Organisms Safety Evaluation Management Procedures", "Agricultural Genetically Modified Organisms Import Safety Management Procedures" ", "Agricultural Genetically Modified Organism Label Review and Approval Procedures"; in July 2002, the Ministry of Health promulgated the "Genetically Modified Food Hygiene Management Measures", and on June 12, 2004 promulgated the "Entry and Exit Inspection and Quarantine Management Measures for Genetically Modified Products", etc., and all Has been officially implemented. These laws and regulations have generally stipulated the management scope, management policies, management principles and management methods of genetically modified foods.
At present, my country’s Ministry of Agriculture, Ministry of Health and Ministry of Science and Technology are mainly responsible for the management of genetic engineering and genetically modified organisms/genetically modified foods. The angle of law enactment differs between departments. The "Genetic Engineering Safety Management Measures" mainly provide macro management and coordination of genetically modified organisms from a technical perspective. The "Implementation Measures for the Safety Management of Agricultural Biogenetic Engineering" mainly manages the experimental research, intermediate experiments, environmental release or commercial production of genetically modified crops from the perspective of protecting my country's agricultural genetic resources, agricultural bioengineering industry and agricultural production safety. The "Regulations on the Safety Management of Agricultural Genetically Modified Organisms" aims to strengthen the safety management of agricultural genetically modified organisms, protect human health and the safety of animals, plants, and microorganisms, protect the ecological environment, and promote research on agricultural genetically modified organisms. The Regulations stipulate that the agricultural administrative department of the State Council is responsible for the supervision of the safety of agricultural genetically modified organisms nationwide. The state implements a hierarchical management and evaluation system for the safety of agricultural genetically modified organisms, establishes a safety evaluation system for agricultural genetically modified organisms, and implements a labeling system for agricultural genetically modified organisms.
"Measures for the Administration of Safety Assessment of Agricultural Genetically Modified Organisms", "Measures for the Administration of Safety of Imports of Agricultural Genetically Modified Organisms", "Measures for the Administration of Labeling of Agricultural Genetically Modified Organisms", "Management Procedures for Safety Assessment of Agricultural Genetically Modified Organisms", and "Management of Safety Assessment of Agricultural Genetically Modified Organisms" issued by the Ministry of Agriculture "Procedures" and "Procedures for Review and Approval of Labeling of Agricultural Genetically Modified Organisms" are the refinement and specific implementation of the "Regulations on the Safety Management of Agricultural Genetically Modified Organisms". The "Regulations on Hygiene Management of Genetically Modified Foods" issued by the Ministry of Health governs the quality, safety and hygiene of genetically modified foods.
Nowadays, the Ministry of Science and Technology, the Ministry of Agriculture, the Ministry of Health, the State Entry-Exit Quarantine Bureau and the State Environmental Protection Administration are paying more and more attention to the safety of genetically modified organisms/genetically modified foods, and are paying close attention to the relevant international management regulations. trends, and is preparing to formulate a unified biosafety law and genetically modified law.
In our country, scientists are also clearly divided into two groups regarding the safety of genetically modified genes. Chen Zhangliang, president of China Agricultural University, once said, "I am a person who firmly supports genetically modified foods. The United States has been eating genetically modified foods for 6 years, we have been eating them for 3 years, and we have not seen any bad results from eating them. China 50% of soybeans are imported genetically modified soybeans, mainly from the United States and Argentina. These soybeans are mainly used to extract oil. The soybean oil, tofu, soy milk, etc. we eat are actually genetically modified. We have been eating them, but they are not No problem." He also said that the hepatitis B vaccine we injected was a genetically modified product, and no one raised any doubts.
Li Ning (Professor of China Agricultural University, Chief Scientist of the National 973 Major Basic Research Project): I dare to say that consumers can eat genetically modified foods with confidence. Because they have to go through many tests before they can be put on the counter. Any genetically modified food undergoes more testing for safety than regular food.
Experts believe that because genetically modified crops can better prevent and control pests and diseases, resist drought, increase yields, and have high nutritional content, they have broad development prospects. By 2015, the global population will increase to 9 billion. Only by improving agricultural productivity can we meet human demand for food, and modern biotechnology is undoubtedly one of the important means to improve agricultural productivity. People can also use genetic technology to produce fast-growing fish and vaccines required for the pharmaceutical industry to meet human needs. However, experts also emphasized that the development of genetically modified foods must have strict supervision, scientific testing, and international legislation to avoid damage to human health and the environment.
This is where I will introduce the safety issues of genetically modified foods to the students. Goodbye, students!