The safety of genetically modified foods has always been a topic of great concern to the public and there are many opinions. Recently, Yang Xiaoguang, a researcher at the Institute of Nutrition and Food Safety of the Chinese Center for Disease Control, gave a special report on “Food Safety Evaluation of Genetically Modified Plants†at a seminar organized by the Plant Protection (China) Association on “Agribiotechnology and Food Safetyâ€. After receiving an interview with reporters. He said that food can not be absolutely safe, China's safety evaluation standards for genetically modified foods are very strict, genetically modified foods at least not more insecure than other foods.
1 "Security" is not absolute
Yang Xiaoguang said that "genetically modified foods" are also foods, and the Codex Alimentarius Commission (CAC) defines food safety as: "Food that has no direct or potential adverse effects on consumer health, we think it is safe."
Here is the CAC. CAC was established in 1961 by the World Food and Agriculture Organization of the United Nations and the World Health Organization to develop various food standards. It is the only government-to-government organization to harmonize food standards and methods and establish the only international agency of the Codex Alimentarius. However, why do we have to listen to your CAC when people of all countries in the world eat each other? So, at the beginning, the standard it gave was "voluntary adoption standards." However, with the International Trade Organization (WTO), many countries have participated in the organization to conduct business with each other, and it is inevitable that friction will occur because of different standards. Therefore, the WTO has set the standards of the CAC as the criteria for solving the problem of food trade scoring. As a result, the standards set by the CAC have become a quasi-compulsory standard. China's safety evaluation of genetically modified foods has largely been based on the relevant CAC regulations.
Yang Xiaoguang emphasized that food safety is a relative concept. “Many people want food to be zero-risk, but this is not possible. Eating anything is a risky event,†said Yang Xiaoguang. Traditional foods are not absolutely safe. For example, lentils are poisonous if they are not heated sufficiently. In fact, every year people are poisoned by eating uncooked lentils.
2 The core is "risk analysis"
CAC follows a "risk analysis" principle. Its core is the hazard assessment: What are the hazards in describing food, what are its characteristics, and what is the exposure to humans? Yang Xiaoguang cited a typical example of a “risk analysis.†In the 1970s, Japan had a serious food contamination incident. Many people suffered from leeches due to the presence of methylmercury in the fish they ate. Methylmercury is more toxic than inorganic mercury. It is discharged into seawater with contaminants and then gradually enriched in the fish. After entering the human body, it causes serious damage to the brain.
At that time, the World Health Organization Joint Food Additives Experts Committee (JECFA) introduced the risk of methylmercury in pregnant women's hair. Every week they eat more than 340 grams of fish, and organic mercury in the blood may reach dangerous concentrations. The United States attaches great importance to this information, and organizes human research to discover that 6% of pregnant women have higher levels of methylmercury in the blood than the United States National Environmental Protection Agency (EPA) recommends. Subsequently, the EPA notified the Food and Drug Administration (FDA) and other departments about the situation and disclosed the results to the fishery sector and the public.
In fact, there are several countermeasures for the risk of consumption of methylmercury in fish. The absolute “zero risk†approach is to prohibit the purchase and sale of fish with high levels of methylmercury. However, the United States has not done so. Because fish is a natural food for humans, humans have been eating fish. This also involves interest issues. If the trade in these fish is banned, the fishery industry will suffer heavy losses. As a result, the FDA has established the maximum pollution limit for methylmercury in fish, limiting the trading of over-specified fish.
Then there was an interesting thing. The FDA regulated that the methylmercury content in fish should be greater than 0.5 PPM (parts per million, ie 0.5 grams of methylmercury in 1 ton of fish). Later, the fishery community initiated a lawsuit against the FDA and the FDA lost the case. This value was raised to 1 PPM. Moreover, in fact, the United States did not use 1PPM as a cut-off threshold, but instead used an informed method to warn those high-risk groups that it is best not to consume which kinds of fish, and the limits of these fish. This is enough to show that even the United States, which attaches great importance to food safety, cannot achieve the "zero risk" of food safety.
3 "Transgenic" is too complicated
Genetically modified foods are essentially different from those mentioned above such as methylmercury. Traditional risk analysis is aimed at a clear substance, such as pesticides, veterinary drugs, and its content in food is very small, it is easy to find the relationship between its dose and human response, so as to find the lowest harmful content. But the composition of food itself is too complicated. It is difficult to make it "more than the actual number of times consumed" in the experiment, so it is difficult to obtain a causal relationship of toxic effects.
There have been some papers discussing the toxicity of genetically modified foods. However, when other scientists review these papers and experiments, they often find that the design of these experiments is not reasonable enough to reproduce the conclusions. For example, in the famous Puezai experiment, rats were only fed genetically modified potatoes and adverse reactions were found. Later, scientists re-examined that eating only any type of potato caused malnutrition in rats, so it was not possible to explain the toxic effects of genetically modified potatoes.
However, there is always a way to test GM foods. Therefore, the International Economic Cooperation Organization proposed the principle of "substantive equivalence", which was later adopted by the CAC. The principle is to analyze the various components of genetically modified foods and compare them with similar traditional foods. If there is no significant difference between them, then it is considered as safe as traditional foods. In simple terms, it is to remove the ingredients in the food as they are and then enter the field of analysis that science is good at.