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GM food testing and evaluation of hazards and

Published:2014-12-08Author:Source:Views:885

In the early 1980s, the United States conducted the first study of genetically modified organisms. The first case of GMOs (Genetically Modified Organism, GMO) in 1983, the advent of genetically modified crops (1986) approved field trials, extension cooked fresh tomato (1993) (Calgene Inc.) approved in the United States, creating transgenic plants for commercial applications precedent. The next six years, its rapid development, than people expect. 1998 global GM crops and planting area of 27.8 million hectares in 1999 to $ 39.9 million hectares, an increase of 44%. 1995-1998 GM crops worldwide sales soared from $ 075 million to 12-15 million. 4 years increased 20-fold. So far, the US has approved 50 kinds of products commercialized transgenic plants, farmland 1/4 of planting GM crops, including genetically modified herbicide-tolerant soybeans accounted for 55% of the total area of US soybeans, 30% of the total area of genetically modified maize. The US market has nearly 4000 kinds of food from genetically modified organisms. According to the International parties predicted that by 2010, the world's genetically modified food acreage will increase to 60 million hectares, the total market revenue will reach $ 3 trillion, and its seed revenue will reach $ 120 billion. Thus it is no exaggeration to say that a new era of genetically modified food has arrived.

 

With the development of GMO's, has recently attracted worldwide a GMO, food security debate. Support and opposition factions outdone, irreconcilable. For this reason, genetically modified organisms safety has become an important topic of previous Assembly of States Parties, international and regional organizations, civil society and other discussions. This article is about the presence of genetically modified organisms and food safety issues, Summary of testing and evaluation are as follows.

 

  First, turn the safety of genetically modified foods


GMO department one or more plants or animals and even human genes into a certain kind of creature, thus demonstrating their nature can not be owned by the transferred genes bring new features, to improve the quality of their products, improve nutrition, increase their resistance to disease, insects, damage, increase production, anti-reverse, extend shelf life and so on. Genetically modified foods (Gene Food) system to genetically modified organisms as raw materials, processing of products for human consumption. GMF is a new technology.


1. The main deficiency of transgenic technology itself


(1) inaccurate technology: genetic technique a heterologous gene from a biological into another organism, although it is possible to accurately cut DNA, but can not be accurately implanted in the new gene in another organism, thus affecting the the basic biological function of other genes. Generate new, unknown protein gene of plant scientists can not foresee, too, can not be completely accurate predictions of the results of the receptor, the performance is not yet mature.


(2) Side Effects: gene technology like movable heart surgery as a surgeon, scientists can not fully, be known in advance of biological DNA surgery, may lead to mutations on the environment and human harm. Although the experiment is very mature, faced strong pressure from nature, can not grasp all the possible impact on human data.


(3) extensive crop production: gene technology through continuous selling seeds for profit, which means that when the farmer planting seed gene, the same gene planted all the plants. When fungi, viruses, insects attack these particular plants will yield serious cuts.


(4) seriously affects the entire food supply: insects, birds, wild animals carrying the genes of seeds into nearby fields, when the transgenic plants produce pollen, they will cross granted spend gene crops and wildlife of all crops , organic or inorganic susceptible to contamination through cross-grant flowers.


2. on the natural environment and health hazards


(1) No longer conduct safety tests: gene altered the natural properties of the food we eat food, and some of the biological material is not used for human food safety it provides, prolonged safety tests not performed, there is no people know this kind of food in the end is not safe.


(2) produce toxins: gene-based foods can produce unpredictable biological mutation, will produce higher levels and new toxins in foods. Losey, JE et al (1999) reported that in a plant milkweed leaf sprinkled transgenic Bt corn pollen, the monarch Kexi Pu Pu tired edible leaf is small, grow slowly, and four days of larval mortality 44 %. While the control group (fed not spread pollen from Bt corn leaf) without a death. Insecticidal toxins produced by genetically modified crops around the roots penetrate, but it is unclear what kind of impact.


(3) allergy or allergy: Gene technology will produce unforeseen and unknown allergens in foods. According to the report, Brazil nut allergic subjects will also use the nuts obtained genetically engineered soy allergy. Scientists transplanted to Brazil nuts characteristics soybeans up, result being that some people who are allergic to nuts may have allergies while soy intake. Lectins (Lectin) is toxic to some insects for genetically modified foods must not contain these toxic substances.


(4) reduce the nutritional value of food or degradation of important food ingredients: The purpose of the gene are believed to remove or inactivate undesired substances that may be unknown, but it is essential. For example it has a natural ability to inhibit cancer (Pariza, MW, 1990). American studies show that soybean herbicide resistant genes, hormones and other ingredients isoflavones reduced cancer prevention. False freshness of food gene confuse consumers. Aromatic, shiny red tomatoes can be stored for several weeks but lower nutritional value. When consumers buy fruit or vegetables, rely solely on the appearance and texture, therefore, can not accurately determine the true quality of the product. Nutrients in the environment will be disturbed natural circulation of genetically modified micro-organisms.


(5) to produce antibiotic-resistant bacteria: antibiotic resistant gene technology (such as anti-kanamycin, ampicillin, neomycin, streptomycin, etc.) to identify genes of genetically modified crops, which means that crops with antibiotic-resistant genes. These genes by bacteria and affect us. British research shows that transgenic crops gene mutations may enter into a living organism, such as gene mutations across populations and transferred to the bacteria, the result may lead to new diseases. Although this opportunity is unlikely, but if there is no cure and widespread life-threatening illness, the consequences could be disastrous. Dutch scientists published in the test results, "New Scientist" magazine, said the design of an artificial stomach human digestive process of genetically modified foods to simulate stranded DNA found in the intestines, while some genetically modified bacteria can put their antibiotic resistance gene transfer to artificial gastric bacteria. If similar results occur in humans and animals, it is possible to cultivate the effectiveness of the strongest, antibiotics can not kill superbugs. Britain's new food and craft advisory committee to ban one kind with ampicillin resistance gene for identification of genetically modified corn fed cattle trend, because it contains the DNA remains intact, and there is likely to accelerate the development of bacterial resistance to antibiotics.


(6) problems can not be tracked: If identified, our inability to public health authorities because of problems found in its origin, the potential harm is questionable.


(7) the side effects can kill the body: Mayeno, AN et al (1994) reported the occurrence of a new, unexplained illnesses, mainly for eosinophilic myalgia. Clinical manifestations of paralysis, neurological problems, painful swelling, itchy skin, heart problems, memory deficits, headache, photosensitivity, weight loss (Brenneman, DE, etc., 1993; Love, LA et al., 1993). After the identification of the Department of Health and a Japanese company tryptophan genetic engineering bacteria due. Eaters in the three months after the onset, leading to 37 deaths and 1,500 body parts paralysis, weakness occasionally occur more than 5,000 people. According to the determination content of 0.1% can kill human body.


3. direct harm to the animal body


Lancet magazine October 16, 1999 report, Pusztai Scotland Rowett Research Institute, A. (1998) for the first time with a turn snowdrop coagulation factors (GNA) gene of potato fed rats, 10 days later, the group found that rats fed colon, jejunum and part of the small intestinal mucosa thickening, but not fed GM potatoes group found no lesions. He thinks, perhaps gene activation or prevent the results of other genes in plants. Also observed in mice kidneys, thymus and spleen abnormal growth or shrink or grow properly, multiple vital organs are damaged, brain atrophy, the immune system is weakened. Although the British Royal Society of Medicine this specialized organization of scientists conduct research, believes that the presence of the experiment from the design, implementation, and many other flaws in the analysis should not be too early to conclude that there is a difference, although the two groups, but due to the experimental techniques restrictions and incorrect use of statistics, these differences can not explain the problem. But still can not dispel doubts about genetically modified foods. Cows produce recombinant hormone (rbGH) in the United States put into commercial use, users quickly discovered these drugs has led to increased incidence of mastitis in dairy cows, cows low reproductive rate. Because of the role of the drug, so the cow's metabolism to speed up, resulting in increased energy consumption and cause death. Nutritional value of milk is also reduced. Allowed to conduct targeted research scientists in Spain and the United States for commercial cultivation of genetically modified corn and cotton thinks that GM crops can cause meningitis and other new diseases. Also has information confirmed genetically modified foods may cause cancer and passed to the next generation as well as lead to disorders, may take 30 years or longer.


Gene therapy drugs, human tissues and organs, such as whether the impact on human health. Still unable to detect confirmed.


The impact on the environmental


(1) an increase in herbicide use: Scientists estimate that genes of crops resistant to herbicides, the actual dose should be three times higher than normal. Farmers know that their crops are resistant to herbicides, will be a substantial use of herbicides.


(2) an increase in the use of pesticides: GMO crops, often using their own unique pesticides, EPA will be classified as pesticides, which means there are more pesticides into our food and fields than ever before. It has been reported, the excellent specific genes (such as anti-pesticide) implanted crops, wild plants around together may make access to improved, showing a characteristic of the anti-pesticide.


(3) ecology has been destroyed: GMO food chain affected by the local ecological environment, new microbes and biological kinship has effectively competitive, causing environmental damage occurred is not visible. As artificial as GM crops could become exotic species that do not exist in nature, after some years, may be soil, wild relatives, ordinary crops, adjacent plants and damage to the environment.


(4) genetic pollution is difficult to eliminate: genes of organisms, bacteria, viruses, etc. into the environment, preservation or restoration is not possible, it's not like chemical or nuclear contamination, deputy face hazards that may be irreversible.


(5) GM crops can make wild relatives through gene flow into the weeds, a "super weeds." Data shows that, after the release of GM canola, when weeds have relatives nearby canola field in progeny seed germination has been proven to be 93% among weed species.


(6) there is damage to non-target organisms, a threat to biodiversity: Hilbeck (1998) fed with genetically modified Bt maize European corn borer (ECB), and use it as lacewings feed, GN fed corn as general controls. The results, edible transgenic Bt corn over 60% mortality in the control group mortality rate below 40%, Bt-related factors considered relevant, surviving lacewings fed Bt corn in the mature group than the control group the average time late 3 days. Birch, A., Etc. (1996/7) of the experimental results showed that the transgenic potato aphid feeding, female fecundity reduced by 1/3, with fed GM potatoes grown male mating aphids and aphid control group, resulting more than four times the number of unfertilized eggs have been fertilized in the mortality rate nearly three times higher than the control group, transgenic potato aphid insects for food floating female survival time is less than half of the control group, if a large-scale cultivation of genetically modified before unhatched crops may reduce populations of beneficial insects.


In fact, our understanding of DNA is limited to 97% of the human genome known as "waste" because we do not know its many features. Single cell metabolism is quite complex, which makes it harder to understand the whole process.


Second, the transfer of organisms to detect genetic progress


Although the safety of the public are increasingly concerned about genetically modified foods, but the price to be separated genetically modified crops and non-GM crops is quite high. Food from farm to table to go through a number of links, each link has a large number of participants, to separate genetically modified crops and non-GM crops can be said to be difficult.


At present, the detection of genetically modified crops made progress. GM ingredients detection must be fast, accurate, sensitive and reliable, while varieties of agricultural products containing genetically modified ingredients in large quantities, especially those containing genetically modified ingredients in food, ingredients complex, to be detected ingredients (nucleic acid or protein) often have been degraded or destruction, or only a small amount of genetically modified ingredients proportions, it is very difficult to detect.


By genetically modified ingredients unique DNA sequence to prompt the gene expression profile. First, the manual inspection, in the traditional biological laboratory using artificial measurement, but slower than a dozen fragments of DNA sequences (about 4000 base pairs) was measured at least one working day. Second, detection equipment, PE3700-DNA sequence analyzer and similar instruments, a working day can be measured nearly 2000 DNA sequences (about 700,000 base pairs). RHM British technology company in March 1999 announced the invention of a new method, which can accurately test the deep processing of foods is the ratio of specific trace genetically modified soybeans or corn ingredients and ingredients containing transgenic ingredients. According to the researchers, they had a piece of bread were investigated and found that 0.67% of the soy-containing ingredients were further analyzed using the new method accurately, they succeeded in finding these trace soy flour in 2% of genetically modified ingredients. Third, chips, Shanghai Institute of Cell Biology (1999) developed a successful primary form biochip "cDNA arrays", is used to detect changes in gene expression profiles in biological samples. There is a biochip immature 15 minutes to complete the determination of 16,000 base pairs, 96 such biochips parallel work, the equivalent of 147 million daily analytical skills base pairs. California, a company in 1996 to produce the first successful use of DNA chips, and made a "gene chip" systems. In addition, a molecular biological research institute in Russia, the United States, other companies have also invested a similar study, and is committed to expand the range of applications.


According to the China Times reported that the country, China's entry-exit inspection and quarantine departments use new detection methods, most of the import of agricultural products were detected from the detection of genetically modified ingredients. National Plant Quarantine Inspection and Quarantine Laboratory (2000), the principle of the use of bio-chip technology, and explore the "affinity adsorption -PCRHyb-ELISA" detection methods, this method is compared with international known PCR method similar method to solve the transgenic sample testing nucleic acid preparation problems, while reducing testing costs and time, and improve the detection sensitivity and stability, improve the degree of automation of sample testing for a large sample size to detect port. The detection method can detect specific 35S promoter and Nos terminator nucleic acid series, both the presence of the nucleic acid series of GMO in the vast majority of currently known.


Inspection and Quarantine Bureau, Jiangsu Agriculture, Livestock and Food Science Laboratory identified the CTAB method to extract DNA, thus capturing the PCR amplification detection methods to determine whether they contain genetically modified ingredients, which are detected sample reached 2 percent of transgenic ingredients can accurately check out.


Shanghai Inspection and Quarantine Bureau and the Chinese Academy of Sciences Shanghai Institute of Plant Physiology (2000) for the detection of genetically modified rice application object, using PCR technology to trace the rapid extraction method CTAB method to extract total DNA, to identify the gene expression of a wide range of applications GUS reporter gene detection can be detected in samples of rice mixed content in more than 1% of genetically modified rice.

PCR-based molecular marker technology will be widely used in genetically modified organisms and food testing (Kary, B, etc., 1994;. Boyce, O, etc., 1998;. Nobuaki, S, etc., 1998;. Hoef van AMA et al, 1998; etc. Hupfer, C., 1998). It can be both qualitative and quantitative, compared to protein-based immunoassay sensitivity 100 times. However, test results of this technique could also be different. Its credibility and sensitivity by extraction and purification of DNA, DNA analysis of PCR, electrophoresis analysis of PCR products affected by three factors, DNA purification and extraction is the key. If DNA degradation and contamination, the test results will not achieve the desired results. If there is DNA degradation and pollution at the same time, there is the possibility of false-negative results, to detect objects that contain GM material itself, without detection. When contaminants exist, false-positive results can occur, that itself is not genetically modified substances, and the detection of genetically modified ingredients. All these results are likely to cause food sale or the purchaser's economic disaster.


Robert, M. (1999) report, it is noted that genetically modified organisms into food heavy processing required, DNA elements can be removed effectively, edible part of most people will eventually contain no new gene. In this sense, genetically modified foods have lost all memory of the gene had joined. Such as genetically modified soybean gene containing the herbicide, soybean oil refining has been tested and does not contain any genetically modified DNA remnants, but not refined soybean oil can also be found in traces of protein, the process of refining it can be removed. Thereby increasing the difficulty in detection of genetically modified food ingredients. The key problem of food detecting genetically modified ingredients that foods containing salt, oil, sugar, and other proteins, food processed in the DNA extraction process, the DNA to ensure its purity, free from contamination and degradation.


Almost 44% of the EU JRC laboratory ring test method proposed by 1998 can not be analyzed completely on GMO's DNA.


John, B.Fagan (2000) introduces a new method, the gene ID method can avoid the above results, the use of guanidine isothiocyanate extraction method to avoid degradation and contamination of DNA, this method is time-consuming and very expensive. And other water soluble rule can not be avoided. Gene ID method has the following advantages: one able to enter the market of GMO detection; 2 has three detection systems, only three GMO-specific primers are both positive, the presence of gene transfer can be judged as ingredients; three large amount of samples... , 10 times larger than the conventional method, many laboratories to meet only the amount of statistical analysis of the sample;. 4 fast and accurate quantification, within three days or three days may be qualitative or quantitative results obtained;. 5 is widely used in food detect not only raw materials, but also on the different food processing after detection; 6. Quick, 36-24 hours, or three working days to obtain the result. Because quite accurate and credible, considered to have the international advanced level.


This method has been used for beans and corn and its derivatives, such as plastic corn, soybean meal, corn germ, tofu (fat and non-fat), corn flour, non-roasted soy flour, fried corn meal byproduct, processing and complete lipid powder is not baked beans, grilled fat soybean meal, corn gluten pellets (electrophoresis technology is improving), soy protein concentrate, polenta products, soy protein isolate, soy housing, soymilk (lyophilized and liquid), beans, cheese (frozen dry and liquid), the detection of soybean lecithin, soybean oil, beans, leaves, beans baby food, bean sprouts, tofu, beans, sausages and other genetic components. All samples containing detection methods are less than XX% GMO report. GMO is not the entire shipment or production lines and accurate quantification.


US ADM Group of Companies, said the company has established a set of crop identification system that can guarantee the supply of agricultural products to foreign countries, excluding GM crops.


Third, the evaluation


The safety of genetically modified foods is a very important and complex issue and should be treated with caution, do not rush to conclusions.


1. Necessity of food safety evaluation: traditional breeding has 100 years of history, it is limited in the kind or sexual crosses between closely related species, no one has ever raised the issue of biological safety evaluation. The genetically modified foods through genetic engineering methods, in accordance with the intent and purpose of human biological design traits, is clearly different from traditional breeding methods. The use of genetic engineering genes derived from any biological boundaries, between species was completely disrupted. To express new combinations and traits appear in different genetic backgrounds, the impact on the environment and human lack of understanding, and some even ignorant, and therefore genetically modified organisms and food safety evaluation is absolutely necessary.


2. Food safety evaluation should pay attention to several issues:

(1) Security is a relative and dynamic concept, with the passage of time and improve the scientific level of food safety awareness may change;

(2) At any time the food supply can not be 100% secure. Such as aflatoxin contamination of food, such as shellfish toxins are still happen;

(3) 100% of the harmful effects of the lack of evidence is never impossible to achieve. No one has been found in transgenic plants lecithin, soybean or soybean starch after consumption of any potential health hazards. In the absence of any hypothetical situation to design a sensitive test is impossible. Food safety testing is the most important issue raised issues related to science and to be answered, if safety analysis included all possible variables, it will be too complicated and difficult to dispose of. Conversely, if the observation of only a few variables, some of the important factors that could be ignored.


Principle 3. Economic Development Cooperation (OECD) (1993) proposed a food security analysis - substantial equivalence (Substantial equivalence) principle, food and food ingredients that biotechnology is currently on the market has substantial food equivalence (WHO, 1995; FAO / WHO1996). Content ratings include natural toxic substances, nutrients and anti-nutritional factors, allergens, and other process traits. WHO (1995) this is divided into three categories, one is traditional and commercial goods have "substantial equivalence"; 2 is in addition to some specific differences, and marketed traditional commodities have "substantial equivalence"; 3 and traditional foods are not "substantial equivalence." Taking into account the diversity of genetically modified organisms should be taken case analysis principles, we can not say that genetically modified foods are safe and not safe. Safety assessment of GM foods include: whether the security toxicity, with or without allergies, as well, such as antibiotic resistance marker genes. However, FDA scientists worry that genetically modified foods may bring new toxins and allergens, using a simple "Substantial equivalence principle" can not find these emerging issues. WHO experts also suggested that GM food safety assessment should consider the type of consumer, exposure levels, changes in the impact of food processing on food safety and nutrition and potential ingredients.


The challenge is to evaluate the protein of unknown allergic allergen sources of difficulties. Common food allergens recommended not to carry out gene transfer.


The safety testing gene transfer: Detection of acute poisoning, most scientists believe that the available short-term animal feeding experiments. The detection of other harmful substances, it must be in human volunteers who participate. If their material is not fatal, it can only cause headaches, animal testing is unlikely to yield results, the rabbit can not tell the investigator suffering from headaches. Allergy In animals results can not be obtained. WHO recommends strengthening research methodology to detect and animal test methods.


Fourth, outlook


Currently, the United States, Japan, EU and other countries, represented by the government, social organizations, biotechnology companies, the safety of genetically modified organisms and food debating Being persistent. Also developed a corresponding strict management approach. GM food safety debate technical issues from rising trade and political issues.


We need to fully understand the advantages of genetically modified organisms, but also attaches great importance to its potential safety problems. So far, both international and domestic security has not been definitely turn modified foods, the potential hazards of genetically modified organisms in genetics and technology has brought instability can not be ignored, the ecological impact and prevent the transgenic plants and wild species, among weeds through pollen spread produce gene transfer need more thorough and effective control. Most crops have been commercialized genetic stability lack of information. To vigorously carry out toxicity of genetically modified organisms and food allergy analysis, accelerate research to identify detection of genetically modified organisms and food, to establish a "GMO safety monitoring" system, the development of scientific management regulations for effective supervision, extensive GMOs science propaganda and correct guidance of public opinion. I believe that, in the context of legal study, released from minority unsafe factors, resilience, resistance to pests, weeds, resistance to Fusarium, good quality, high yield, resistance to drought, frost, increase the added value, such as renewable energy biological advantages will be widely used to solve human problems of food shortages. GM foods are not only readily accept people, but also bring more benefits to mankind.


American scientists are working on a product called "chimera transplantation," the new technology can be implemented either genetically modified, they do not need to implant a foreign gene, as long as take a DNA fragment, which will be combined with the RNA, just as a chemical instructions to the cells to change in accordance with the requirements of the way genes. Recent developments in technology have been able to allow others to identify the gene, rather than with anti-antibiotic genes. The success of these methods, it will be largely free of genetically modified foods cause is difficult to eliminate the "genetic pollution" concerns.

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