The Sanlu “tainted milk powder” incident was exposed like a thunderclap, triggering a great shock in the domestic milk powder industry, and some even predicted that this was a trigger for the restructuring of the domestic milk powder industry. However, for the parents of these infant victims, loved ones, the concern is not the changes in the milk powder industry, but the treatment and rehabilitation of infants, as well as for the parents of other infants who have not yet discovered the problem, the concern is: what milk powder can now eat? And since infant milk powder is a problem, does it also exist in the case of liquid milk, yogurt, ice cream, etc., which are consumed by adults every day, and what milk products can still be consumed? This brings us to the question of how the melamine added to the “tainted milk powder” was detected. On September 13, Xinjing News reported that “authoritative testing departments and food experts confirmed that the state rarely tested melamine in milk powder products, and there is no particularly effective testing method” and that “at present, the district and county health supervision and disease prevention and control departments in Beijing do not yet have the ability to detect melamine in food. At present, the health supervision and disease prevention and control departments in Beijing do not have the ability to detect melamine in food. This means that there is no particularly effective way to detect melamine in the national supervision department. So what exactly is melamine? Melamine (cyanuramide), molecular formula C3H6N6, also known as honeyamine, 2,4,6-triamino-1,3,5-triazine. White monoclinic prismatic crystal. Melting point 345℃ (decomposition), density 1.573g/cm3 (16℃). Slightly soluble in water and hot ethanol. Melamine is industrially produced by reacting dicyandiamide with ammonia at high temperature or directly from urea at high temperature and pressure, the latter is low cost and more often used. Last year’s “pet food poisoning” incident was caused by this chemical, when the U.S. FDA found in the investigation of successive deaths of dogs and cats, the main raw material of several well-known brands of pet feed wheat protein powder and rice protein concentrate, both containing the chemical melamine. The FDA’s investigation ultimately confirmed that melamine was the main culprit in the deaths of pets in wheat protein powder and rice protein concentrate. In general, the analysis of melamine is mainly done by high performance liquid chromatography, which is a tedious and costly process, and in the production process of milk powder, the testing indicators that are often done are: brewing, insolubility index, impurity degree, moisture, protein, fat, etc., while some other physical and chemical properties of foreign testing indicators such as surface free fat, weight, wettability, dispersibility, etc. are rarely tested in China. The testing is rarely done in China. As melamine is a chemical material, it is not allowed to be added to food, so the existing standards will not contain the corresponding content, and domestic milk powder testing will not be tested in this regard. At that time, after the “pet food” incident in the United States, there were several companies producing and selling enzyme-linked immunoassay (ELISA) test kits for melamine. For example, the AgraQuant Melamine Test Kit from Rome Labs, Beacon Melamine Plate Kit from Beacon Analytical Systems, Melamine Plate kit from Abraxis, Strategic Diagnostics’ EnviroGard Triazine Plate kit, etc. The FDA’s eric Garber also compared the products of Abraxis and Strategic Diagnostics and concluded that the former method is simpler and has comparable or even better performance, as published in this year’s Journal of Food Protection No. 3. Compared with chromatographic methods, enzyme-linked immunoassay (ELISA) is of course much simpler and more convenient, as the former requires sample extraction, column purification and concentration before HPLC analysis or GC/MS analysis after derivatization, and this chromatographic method is used by the U.S. FDA and the Chinese Ministry of Agriculture for melamine detection, with little difference in procedures. The lower limit of detection for chromatography is said to be 20 ppb, and the cost of testing each sample is about 400 yuan for a week. The latter ELISA, that is, the enzyme-linked immunosorbent assay, uses the immunological technique to determine the specimen, the basic principle of which is the specific recognition of antigen antibody. Using the ELISA method, melamine needs to be extracted from the sample first, and then the melamine HRP enzyme coupling, sample extract and standards are added together to the microtiter wells packed with melamine antibodies to react, and after 3 incubations, the melamine and melamine HRP enzyme coupling in the sample bind competitively to the melamine antibodies. This way the unbound melamine and melamine HRP enzyme couplers will be washed off and the chromogenic enzyme substrate added to the microtiter wells and any bound enzyme couplers will make the liquid appear blue. At the end of the reaction a reading is taken with the enzyme standard and the concentration of melamine in the sample is obtained by comparing the reading of the unknown sample with the reading of the standard. The lower limit of detection for this method is 10 ppb, and it takes only 65 minutes. Nowadays, there are not many domestic kits supplying the principle of this method, including imported American Abraxis melamine kits, Beacon melamine kits, and domestic ones such as the enzyme-linked immunoassay kits developed by the Institute of Agricultural Quality Standards and Detection Technology of the Chinese Academy of Agricultural Sciences for detecting melamine. Since the melamine enzyme immunoassay kit method is simple and effective, is it necessary to add the detection of this substance to these standards in the future, or should the current dairy-related standards undergo “major surgery”? When the “lean meat” incident led to the emergence of reassuring meat, pork now need to be mandatory sampling, so is it for melamine “protein essence” also to be mandatory testing, is not also to have “reassuring milk “The emergence of, perhaps only in this way, to solve the current crisis of confidence in domestic dairy products.