Safety evaluation of genetically modified foods

作者：admin  点击次数：133  发布时间：2025-06-30

1. Purpose of safety evaluation of genetically modified foods
The emergence of any new technology is a "double-edged sword". While genetically modified technology brings huge benefits to agricultural production, human life and social progress, it may also cause potential harm to the ecological environment and human health. The key is to weigh the pros and cons and make a choice.
The purpose of safety evaluation of genetically modified foods is:
① Provide a basis for scientific decision-making;
②) Protect human health and environmental safety;
B) Answer public questions;
④ Promote international trade and safeguard national rights and interests;
⑤ Promote the sustainable development of biotechnology.
2. The principle of substantial equivalence and safety evaluation (1) Definition of the principle of substantial equivalence The first FAO/WHO expert consultation meeting held in 1990 discussed general and specific issues in the safety evaluation of genetically modified foods. It was believed that traditional food safety evaluation based on toxicity analysis is not necessarily completely suitable for biotechnology products. The safety of biotechnology products must be determined based on their molecular biology and chemical properties.
In 1993, the Organization for Economic Cooperation and Development (OECD) proposed the principle of substantial equivalence for food safety evaluation. Its meaning is "When evaluating the safety of new foods and food ingredients produced by biotechnology, existing foods or food-derived organisms can be used as a basis for comparison. If a genetically modified food is compared with existing traditional similar foods, its characteristic chemical composition, nutritional composition, toxins contained, and the consumption and feeding of such food by humans and animals are similar, then they are substantially equivalent."

In 1996, the Second Expert Consultation Meeting on Biotechnology Safety Evaluation convened by FAO/WHO recommended that "safety evaluation based on the principle of substantial equivalence can be used to evaluate the safety of foods and food ingredients derived from genetically modified organisms." Substantial equivalence can prove that genetically modified products are not less safe than traditional foods, but it cannot prove that it is absolutely safe, because it is unrealistic to prove absolute safety; the meeting divided the substantial equivalence of genetically modified foods into three categories: complete substantial equivalence with existing foods or food ingredients; substantial equivalence with existing foods and ingredients except for certain specific differences; a certain food has no basis for comparison, that is, it is a brand new food and is not substantially equivalent to existing foods.
(2) Determine the content of comparison for substantial equivalence. For these three different types of GM foods, the differences in their safety evaluations are very large, so it is very important to determine the substantial equivalence of GM foods. Generally speaking, the comparison of substantial equivalence should include the following aspects:
① Comparison of biological characteristics: for plants, it includes morphology, growth, yield, disease resistance and other related agronomic traits; for microorganisms, it includes taxonomic characteristics (such as culture methods, biotypes, physiological characteristics, etc.), infectious host range, presence or absence of plasmids, antibiotic resistance, toxicity, etc.; for animals, it includes morphology, growth physiological characteristics, reproduction, health characteristics and yield, etc.
②) Comparison of nutritional components: including major nutrients, anti-nutritional factors, toxins, allergens, etc. The main nutritional factors include fat, protein, carbohydrates, minerals, vitamins, etc.; anti-nutritional factors mainly refer to some substances that can affect people's absorption of nutrients in food and digestion of food, such as some protease inhibitors, lipase and phytic acid in leguminous crops; toxins refer to some substances that are toxic to humans, such as solanine in potatoes and tomatine in tomatoes in plants; allergenic principles refer to a class of substances that can cause allergic reactions in some people after consumption, such as 2S albumin in Brazil nuts.
(3) Main contents and steps of safety evaluation The main contents and steps of safety evaluation of genetically modified foods can be vividly described by Figure 6-1.
As can be seen from the figure, the procedures for safety evaluation of genetically modified foods include the following aspects: ① Research on the characteristics of new gene products; ② Analysis of changes in the content of nutrients and known toxins; ③ Research on potential allergenicity; ④) The possibility of genetically modified foods exchanging genes with microorganisms in the intestines of animals or humans and its impact: ⑤ Toxicological and nutritional evaluation in vivo and in vitro. It is worth noting that substantial equivalence is a guiding principle, not a substitute for safety evaluation. It is a useful tool for scientists conducting and managing safety evaluations; it provides helpful guidance for questions raised in identification when evaluating the safety of new foods, feeds or processed products, but it is not the end of the evaluation.