Biotechnology represented by recombinant DNA technology is one of the most important high-tech technologies in 2 1 century. The development of modern biotechnology industrialization led by transgenic plants plays an important role in the development of agriculture, rural areas and national economy and social stability in China. After more than 20 years' efforts since 1980, China's development in this field has been at the forefront of developing countries, but there is still a considerable gap compared with advanced countries in the United States and Europe, especially in the understanding of transgenic technology and food safety. This paper briefly introduces genetically modified food and its safety evaluation. First, the development status of genetically modified foods Before introducing genetically modified foods, we must first understand what genes and transgenic technologies are. Gene (DNA) is a structural and functional unit that controls the inheritance of biological traits. DNA is the abbreviation of deoxyribonucleic acid, which encodes various genetic information and produces different protein. Transgenic technology mainly refers to the technology of introducing recombinant DNA molecules into organisms by using recombinant DNA technology and physical, chemical and biological methods. Organisms constructed by transgenic technology are called transgenic organisms, including transgenic plants, transgenic animals and transgenic microorganisms. Therefore, generally speaking, genetically modified foods are foods produced and processed by genetically modified organisms. Adapting to transgenic plants, animals and microorganisms, genetically modified foods can be further divided into genetically modified plant foods, animal foods and microbial foods. Among the above three types of genetically modified foods, the fastest growing is genetically modified plant food. Although China, the United States and Canada have made breakthroughs in fast-growing genetically modified fish, so far, no genetically modified animal food has been approved for marketing in the world. In foreign countries, enzymes produced by genetically modified bacteria and fungi are widely used in food production and processing, but microorganisms such as genetically modified yeast used in bread, beer, yogurt and other foods and beverages have not been allowed to enter the market. Therefore, there are basically only genetically modified plant foods on the market at present. Since 1983, the world's first transgenic crop (tobacco and potato) came out, the research on transgenic plants has developed rapidly. 1994 transgenic tomatoes with extended maturity and fresh-keeping were allowed to be listed in the United States. Since 1996, the commercialization of genetically modified crops has entered a period of rapid development. In 2000, the global planting area reached 44.2 million hectares, and the planting area in 200 1 year still increased by 19% over the previous year, reaching 52.6 million hectares. Among them, the planting area of genetically modified soybeans is 33.3 million hectares, accounting for 63% of the total area of genetically modified crops; Followed by corn, 9.8 million hectares, accounting for19% of the total area of genetically modified crops; There is also a larger area of cotton and rape. Planting country 13, among which the United States, Argentina and Canada rank in the top three. More than 100 varieties of transgenic crops have been approved for marketing in various countries, including tomato, soybean, corn, cotton, rape, rice, potato, zucchini, papaya, beet, chicory and flax 12. Genetically modified crops have produced and processed more than 4000 kinds of genetically modified foods and food ingredients. Among them, soybeans and corn account for more than 90% of raw materials. In the five years from 1997 to 200 1, the global planting area of genetically modified crops has increased by more than 30 times, among which genetically modified soybeans, as the main food raw materials, account for 46% of the total soybean area in the world. After planting transgenic varieties, the yield and quality of soybeans were improved, and the use of toxic pesticides was reduced, which brought benefits to farmers, enterprises and the environment. In 200 1 year, the planting area of genetically modified crops in China ranks fourth in the world, accounting for about 3% of the global genetically modified crops. The crops planted are transgenic insect-resistant cotton. Since 1980, the government of China has always attached great importance to the development of agricultural biotechnology. In the "National High-tech Research and Development Plan" (referred to as "863 Plan" for short), which was launched in March 1986 and became an important milestone in high-tech development, the investment in agricultural biotechnology and medical biotechnology is generally half. Agricultural biotechnology has also been listed as a priority development field in the national key scientific and technological research plan, natural science fund, biotechnology project of the Ministry of Agriculture and other scientific research and industrial development plans. After nearly 20 years of unremitting efforts, a number of national and departmental key laboratories and research centers have been built and developed rapidly. The development system of biotechnology in the agricultural field has been gradually formed, and a series of remarkable achievements have been made, realizing the transformation from laboratory to field to industrialization. 1997 The first transgenic storage-resistant tomato in China was approved for commercial production, and the planting area was very small. The only large-scale transgenic crop is insect-resistant cotton developed by China Academy of Agricultural Sciences and Monsanto. Insect-resistant cotton developed by China Academy of Agricultural Sciences is 200 1 year, and 9 million mu (600,000 hectares) is planted. Insect-resistant cotton developed by Monsanto was also approved for commercial production in 1997. So far, there is no commercial production of genetically modified bulk grain, oil crops and genetically modified animal products. Second, the safety of genetically modified foods The safety of genetically modified foods is a common concern of the global society. Although the safety of every food is closely related to the structure, function, safety characteristics and application environment of the genetically modified organisms used, it cannot be generalized, but in general, all genetically modified foods that have been scientifically evaluated and strictly approved by government departments are safe so far, and there has not been a single case of genetically modified food poisoning or medical accident after hundreds of millions of people in the world eat them. It should be pointed out that no food is 100% safe, including food produced by conventional farming techniques. For example, ergot poisoning, aflatoxin and bacterial food pollution. At the same time, food safety is a relative and dynamic concept. With the progress of science and technology, food that is considered safe today may find unsafe factors tomorrow. Similarly, food ingredients that are considered unsafe today can be deleted or become safe tomorrow through new technologies. We feel more at ease about the food we eat every day because our ancestors gradually realized the unsafe factors of many foods in long-term practice and mastered the techniques of planting, breeding, production and processing to ensure safety. In fact, compared with conventional breeding techniques, the consequences of transgenic breeding should be more accurately predicted than the former. At present, transgenic technology usually transfers only one or two genes with very clear structure and function, so the traits provided by this gene are predictable, while conventional sexual hybridization, especially hybridization between distant species, transfers thousands of genes. Therefore, as a dragon, we can also master the technology of safe use of genetically modified food. It is known that 2S albumin of Brazil nut has allergic reaction to some people. Scientists have transferred the 2S albumin gene from Brazil nuts into soybeans. Further research found that genetically modified soybeans still have allergic reactions to some people, so this research was automatically terminated at an early stage and did not enter the market. This is the only case of allergic reaction of genetically modified crops found so far. This shows that scientists and government regulators are highly responsible for public health and safety. It should also be pointed out that transgenic technology can also increase the safety of the environment and food. For example, the mycotoxin on the ear of transgenic Bt corn is 30~40 times lower than that of non-Bt corn, which is beneficial to health and product export. Because Bt cotton sprayed less pesticides, the number of natural enemies of cotton aphids in the field increased greatly, and the population density of aphids was 440~ 1500 times lower than that in conventional cotton fields. Scientists are also developing techniques to remove allergic proteins from traditional foods. People are worried about the safety of antibiotic marker genes in transgenic crops. In fact, the resistance of bacteria to antibiotics is getting stronger and stronger, which is not caused by genetically modified crops, but by the abuse of antibiotics in the treatment of human and animal diseases. Scientifically speaking, there is no mechanism or evidence that antibiotics in food will infect horizontal gene transfer to intestinal bacteria and intestinal epithelial cells. The reason is that the DNA in food has become a fragment when it enters the intestine, not a complete gene; Intestinal bacteria need to be activated before foreign genes can be transferred; Promoters used in transgenic plants are not suitable for gene expression in bacteria; And there is no selective pressure of antibiotics in the intestine. In response to public concerns, scientists have developed a technology to delete antibiotic marker genes from genetically modified crops. They can also use safe marker genes or not use any marker genes. In view of the great development prospects and potential economic benefits of genetically modified crops, more than 3,000 scientists have signed the declaration in support of biotechnology all over the world (from 1.09 in 2000 to now), including many famous figures such as norman borlaug, the father of the Green Revolution and the Nobel Prize winner. Seven academies, including the American Academy of Sciences, the Royal Society, the China Academy of Sciences and the World Academy of Sciences, also issued a joint statement in support of biotechnology. Four. Safety evaluation and supervision management of genetically modified foods (I) Why should we evaluate the safety of genetically modified foods? The emergence of any new technology is dual and a double-edged sword. Cars, planes, nuclear technology and so on are all the same. While benefiting mankind, cars will cause air pollution, planes will crash, and nuclear technology can be used in war. Transgenic technology represented by recombinant DNA technology not only brings great benefits to agricultural production, human life and social progress, but also may bring potential risks to the ecological environment and human health. The key is to weigh the pros and cons and make a choice. It should also be pointed out that danger and risk are two different concepts, and potential risk is not equal to real danger. Safety assessment is to analyze potential risks and avoid them. Agriculture is the main application field of transgenic technology. Establishing the safety evaluation system of agricultural genetically modified organisms is a common practice all over the world, and it is also the main content of Biosafety Protocol. The reason to evaluate the safety of genetically modified crops and their food is that transgenic technology can transfer genes between animals, plants and microorganisms, and even introduce large fragments of multi-genes into organisms for expression, so scientific evaluation is needed. In recent years, the safety of genetically modified organisms (GMOs) has become a hot topic of international debate, which is not purely a scientific issue in essence, because scientific issues can be solved through scientific research, but involve many aspects such as trade, economy, politics, society, religion, ethics and so on. In order to conduct safety assessment, many countries have formulated laws and regulations on biosafety to manage genetically modified organisms. As a large agricultural country, China has diverse biological resources and is also the origin of rice, soybeans and other crop varieties. While strengthening and promoting the research and development of transgenic technology, we must attach great importance to the safety of genetically modified organisms. Therefore, on May 23rd, 20001year, the government of China issued the Regulations on the Safety Management of Agricultural Genetically Modified Organisms by the State Council Decree No.304. (II) Contents of Safety Assessment Safety assessment mainly includes two aspects: environment and food safety. Environmental safety refers to the possibility of causing plant diseases, the change of survival competitiveness, the possibility of gene drifting to related species, the possibility of becoming weeds, and the impact on non-target organisms and ecological environment after transgenic. The safety of food and feed mainly includes nutritional ingredients, anti-nutritional factors, toxicity and allergies. Through the safety evaluation, it can provide a basis for the research, experiment, production, processing, management, import and export of agricultural genetically modified organisms, and also prove to the public that the safety evaluation is scientific. Therefore, the safety assessment of agricultural genetically modified organisms is the core and foundation of safety management. (3) Safety evaluation should be based on science and scientific data and stand the test of history, which is the basic principle that safety evaluation must abide by. It usually takes 6-7 years for a product to be approved for marketing. Based on this principle, governments and biosafety committees all over the world have made a realistic and scientific evaluation on the safety of genetically modified plants and their foods to human health and ecological environment. Therefore, under the premise of ensuring safety, it has effectively promoted the development of transgenic technology and genetically modified food. In the past three years, the international debate on the safety of genetically modified crops mainly focused on several incidents, and now it has been proved that some reports lack scientific basis. For example, in the Puztai incident, Dr. Arpad Pusztai of Rowett Institute in Scotland reported that the potato transgenic with snowdrop agglutinin gene "reduced the weight and organ weight and destroyed the immune system" after feeding rats. 1After organizing peer review in May, 1999, the Royal Society pointed out that there were six defects in Putztai's experiment, that is, the chemical composition of transgenic and non-transgenic potatoes could not be determined; Mice fed with genetically modified potatoes did not supplement protein to prevent hunger; The number of animals tested is very small; The food fed is not the standard food for mice; The experimental design is poor, and no double-blind determination is made; Improper statistical methods and inconsistent test results. Another example is the butterfly incident. 1In May, 1999, a research team from Cornell University reported that Bt corn pollen scattered on milkweed leaves could kill 44% of butterfly larvae. Science refused to publish this article, and the reviewers pointed out that this did not represent the situation in this field. Recently, a special article was published in the Journal of Plants, which provided the data of recent experiments in the United States and Canada, and pointed out that transgenic corn pollen had no effect on the survival of butterflies in the field, and the death of butterflies was caused by the extensive use of pesticides and the destruction of Mexican habitats. The conclusion is that transgenic corn is not a threat to butterflies. Another example is the recent corn incident. Mexico is the origin center of corn. It is reported that the promoter sequence of cauliflower mosaic virus 35S was detected in wild corn varieties in Mexico, which was proved to be false positive by Swiss Academy of Medical Sciences and Mexico International Maize and Wheat Improvement Center. These facts show that safety evaluation must be based on science and stand the test of practice and history. At the same time, it should be pointed out that due to the short history of transgenic crops, some long-term effects need to be tracked and monitored, such as pest resistance management of Bt crops, long-term ecological effects of herbicide resistance, virus recombination and heterogeneous packaging, food toxicity and allergies. (IV) Food Safety and Label Management It is an internationally accepted practice to implement safety management for agricultural genetically modified organisms. OECD, FAO, UNEP, Biosafety Protocol and Codex Alimentarius Commission all put forward clear requirements for the safety of genetically modified organisms. Safety assessment is an international practice. Due to the differences in agriculture, environment and biodiversity in different countries, it is decided that genetically modified organisms can only be put into commercial application or introduced by exporting countries after their own safety is confirmed. Japan, the European Union, the United States and other countries have carried out safety evaluation. The United States only allows commercial production of genetically modified crops after passing the safety assessment of the Ministry of Agriculture, the Food and Drug Administration and the Environmental Protection Agency. The EU only approved the introduction of genetically modified products at home and abroad after passing the safety assessment. Japan is only allowed to import genetically modified agricultural products after passing the safety assessment of the Ministry of Agriculture, Forestry and Fisheries. At present, according to the relevant provisions of the Biosafety Protocol, the safety assessment and management of imported agricultural genetically modified organisms can be carried out within 270 days from the date of receiving the application. In the process of formulating "Regulations" and its supporting laws and regulations, China made a comparative study of relevant foreign laws and regulations. Safety evaluation should follow the principles of "case analysis", "substantial equality" and "gradual improvement". The implementation of logo management system is to give consumers the right to know and choose. In 1980s, while China was carrying out research on transgenic technology, relevant departments in the State Council attached great importance to the safety of genetic engineering. 65438-0993 The former State Science and Technology Commission promulgated the Measures for the Safety Management of Genetic Engineering. According to this method, in July of 1996 and 10, the Ministry of Agriculture promulgated the Implementation Measures for Safety Management of Agricultural Biogenetic Engineering, and established the Safety Committee of Agricultural Biogenetic Engineering and the Safety Management Office of Agricultural Genetic Engineering. From 65438 to 0997, the Ministry of Agriculture began to accept the safety evaluation and approval of genetically modified plants, animals and microorganisms engaged in genetic engineering research, experiments, environmental release and commercial production in China, and conducted strict safety evaluation on the commercial production of genetically modified organisms and their products. Up to 200 1, the Ministry of Agriculture has accepted more than 700 applications for safety assessment of agricultural genetically modified organisms 10. The development of the above work has gradually put the safety management of agricultural bio-genetic engineering in China on the track of standardized management, which has played an important role in promoting the healthy development of agricultural biotechnology research in China, safeguarding the development of national biotechnology industry and the safety of genetically modified agricultural products, and protecting the agricultural ecological environment and human health. In a word, modern biotechnology represented by genetic engineering technology has great potential and bright prospects in agriculture and other fields. This is both an opportunity and a challenge for us. The development of science and technology is irreversible, and we believe that the debate about genetically modified plants and food is only temporary. According to the international development trend, comprehensive science and technology, trade and other factors. Formulating policies for the development of transgenic plant industry and biosafety management suitable for China's national conditions will be beneficial to the healthy development of agricultural biotechnology industry in China and take the initiative in international competition in the new century. If we are confused by the superficial phenomenon of international debate, or wait and see, hesitate or slow down the development, we will miss the opportunity and ruin our existing advantages in the research of genetically modified plants in vain, and as a result, we will be passive in international trade and scientific and technological competition. Therefore, we should actively and steadily promote industrialization on the basis of strengthening safety management.