In a word, we can only treat it from the source, including introducing hazard analysis from the origin, seeds, conditions, soil and fertilizer of tea. This is the aspect of raw materials, which can be monitored as a key control point, especially the existing toxic and harmful substances, which can be confirmed by inspection. Additives in the process are more important, such as added substances and process methods. What about the finished product? Laboratory tests and tests suitable for people, etc. , can achieve the expected purpose and achieve certain results.