Science Times: it is urgent to develop rapid food detection technology
in February this year, Hainan's "poisonous cowpea incident" exposed the defects of rapid detection technology for agricultural residues in fruits and vegetables
Hainan cowpea escaped routine rapid detection time and time again, and finally the specific varieties and residues of banned high toxic pesticides were found in the chromatographic detection in the laboratory. This makes the media question the rapid detection technology of agricultural residues
at present, the commonly used rapid detection method of pesticide residues in China is enzyme inhibition method. Why does enzyme inhibition rapid detection technology make highly toxic pesticides leak again and again? What is the development prospect of rapid detection technology in the field of food safety? Science Times recently interviewed several industry experts
why is the rapid detection method of pesticide residues "lax law enforcement"
in the report of the "poisonous cowpea incident", the media pointed out that the rapid detection technology of pesticide residues has many shortcomings: it can only be used for qualitative detection of pesticide residues, not quantitative detection; It can only be used for rough detection. Wuhan uses chromatographic instruments to measure the residue of a few milligrams of Isocarbophos per kilogram, but the rapid detection of agricultural residues in Hainan cannot be measured at all; In addition, there are many false results in the rapid detection of pesticide residues
Wang Jing, chief scientist of standards and detection technology of Chinese Academy of Agricultural Sciences, explained the basic principle of enzyme inhibition method: enzyme inhibition method is used to detect organophosphorus and carbamate pesticides, which can inhibit the activity of acetylcholinesterase or butyryl cholinesterase. People can extract this enzyme from the head of flies or electric eels. During rapid sampling, extract the vegetable juice and add the enzyme reaction solution. If these two kinds of pesticides exist, it will inhibit the enzyme, reduce its activity, and the color of the reaction solution will change, so that it is known that there are pesticide residues
but this method has obvious limitations. Jiang Shiqiang is the executive vice president of the agricultural instrument application technology branch of the China instrumentation society. He said that the enzyme inhibition method was proposed by the United States as early as 1951 and improved by Canada in 1968. China also began to develop it in the 1980s. However, this method can only detect organophosphorus and carbamate pesticides. Organophosphorus and carbamate pesticides contain a variety of pesticides, and the enzyme inhibition rates of the same kind of pesticides are very different from those of the same kind. Therefore, the unified inhibition rate is used to determine whether the pesticide residues exceed the standard. It is inevitable that now cross-linked polyethylene is mostly used to heat, decompose and refine oil, resulting in false positive or false negative missed detection
Wang Jing told that drug cross reactions will also bring complications. In addition, spicy foods such as onions, ginger, garlic and some colored agricultural products will affect the reaction results
due to these limitations, some experts even said that the current enzyme inhibition pesticide residue rapid detection method is "false alarm, full implementation of ISO9001:2000 quality management system inspection" and "Scarecrow"
Jiang Shiqiang said, "the enzyme inhibition method can be said to be only applicable to the primary inspection at the grass-roots level, which serves as a warning. When exceeding the standard is found, it must be retested and confirmed by standard methods. Even if it does not exceed the standard, it should also be sampled in proportion, retested and confirmed by reliable methods, and must not rely solely on the rapid detection instrument of agricultural residues of the enzyme inhibition method. The application of rapid detection methods is clearly defined in Article 36, paragraph 2, of the agricultural product quality and safety law."
Jiang Shiqiang further pointed out that the current enzyme inhibition method in China is only "a quick detection method that has to be used as a last resort", and suggested that the standard for the detection of pesticide residues by enzyme inhibition 1 method should be revised as soon as possible
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