农业生物技术的安全性评价

Agricultural biotechnology safety assessment

转基因作物自1995年开始引入种植，以满足日益增长的粮食和饲料需求。转基因作物用于人类食物和动物饲料需要进行全面的安全性评价，首先从DNA水平考虑，包括插入宿主基因组的是什么DNA，插入的位置和稳定性如何？其次，考虑DNA编码蛋白的安全性及其对作物的潜在效应，确保转入的新蛋白从毒性、致敏性和环境各方面的评价都是安全的，此外，用于食品或动物饲料加工的谷物需要评价其营养成分，必要时还要确定其非预期效应。为给转基因作物的安全性评价提供依据，需要对转基因作物与非转基因对照物进行成分等实质同性分析，质谱及基于抗体的新技术能够对包括内源性致敏原在内的作物成分进行更精确的分析。监管指南文件中提出了许多分析方法及其用途，有一些是全球公认的文件（如食品法典委员会提出的文件）。有些国家的监管机构推荐在某些情况下使用动物模型，但是在转基因作物的安全性评价中，动物模型的使用没有依据。试验方法的质量控制和标准化可以通过采用良好实验室规范来达成，是高质量数据的保证。监管机构对转基因作物的安全性测试方法的要求越来越多，根据目前的评价结果，已经登记的转基因作物与非转基因对照物同等安全。

Genetically modified （GM） crops were first introduced to farmers in 1995 with the intent to provide better crop yield and meet the increasing demand for food and feed. GM crops have evolved to include a thorough safety evaluation for their use in human food and animal feed. Safety considerations begin at the level of DNA whereby the inserted GM DNA is evaluated for its content, position and stability once placed into the crop genome. The safety of the proteins coded by the inserted DNA and potential effects on the crop are considered, and the purpose is to ensure that the transgenic novel proteins are safe from a toxicity, allergy, and environmental perspective. In addition, the grain that provides the processed food or animal feed is also tested to evaluate its nutritional content and identify unintended effects to the plant composition when warranted. To provide a platform for the safety assessment, the GM crop is compared to non-GM comparators in what is typically referred to as composition equivalence testing. New technologies, such as mass spectrometry and well-designed antibody-based methods, allow better analytical measurements of crop composition, including endogenous allergens. Many of the analytical methods and their intended uses are based on regulatory guidance documents, some of which are outlined in globally recognized documents such as Codex Alimentarius. In certain cases, animal models are recommended by some regulatory agencies in specific countries, but there is typically no hypothesis or justification of their use in testing the safety of GM crops. The quality and standardization of testing methods can be supported, in some cases, by employing good laboratory practices （GLP） and is recognized in China as important to ensure quality data. Although the number of recommended, in some cases, required methods for safety testing are increasing in some regulatory agencies, it should be noted that GM crops registered to date have been shown to be comparable to their nontransgenic counterparts and safe. The crops upon which GM development are based are generally considered safe.