The most poisonous milk and meat must show their o

2022-07-23
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"Toxic" milk and "toxic" meat all have their original shape

detection of melamine in milk requires more than 20 processes, and detection of clenbuterol requires millions of yuan of equipment. How exactly do the guardians of food safety guard the safe loading of food? Yesterday, they went to the National Center for quality supervision and inspection of processed food to personally experience the whole process of food safety detection

four steps, one and a half hours to detect melamine

the inspectors of the national processed food quality supervision and inspection center of the municipal product quality supervision and Inspection Technology Research Institute told that in addition to accepting the product testing entrusted by the enterprise, the center also undertakes the tasks of supervision and random inspection, such as national random inspection and municipal random inspection, and often tests 70 or 80 batches of products every day. In order to feed back the test data to the regulatory department at the first time, Overtime has become a common occurrence. For example, there are more than 20 processes to detect whether dairy products contain melamine or not

1. Sample weighing

"weighing is the first step in the sample processing stage." With that, the tester weighed two grams of the milk to be tested and put it in a test tube. The tester told it was called a centrifuge tube, and then skillfully picked up the reagent on the table and poured it into the centrifuge tube

2. Component extraction

"The main equipment used to detect melamine is the high performance liquid chromatograph, which is an automatic analytical instrument capable of detecting trace components. However, it is not possible to directly pour the milk to be detected into the instrument as ordinary consumers imagine. Because this instrument has very high sensitivity, ordinary impurities must be treated and separated, but the melamine component cannot be separated Therefore, the pre-treatment of milk samples is very important. " Xiao Liu, who is in charge of melamine detection in dairy products, said. The instruments used in this process include ultrasonic water bath and high-speed centrifuge. After centrifugation at 4000 revolutions per minute, the solution will be divided into upper and lower layers, and melamine will be located on the upper layer of the liquid

3. Component purification

these solutions need to be purified after preliminary treatment. Because all the tested components are trace components, any foreign impurities will directly affect the test results. Therefore, the purity of various reagents in the laboratory is almost strict. Among them, many reagents require very high purity, such as nitrogen, which must be greater than or equal to 99.999%. There is also the most common laboratory water. Generally, grade III water is used for chemical analysis experiments. But here, grade I water is required for HPLC analysis. This water is generally obtained after distillation and filtration with a 0.2 micron filter membrane. Even containers and air will potentially pollute it. Therefore, this water cannot be stored. It must be prepared in strict accordance with the standards before use

4. Online detection

"more than 20 links are required for extraction and purification." After skilled operation by technicians, two grams of milky milk has turned into a colorless aqueous solution. The inspectors use a syringe to pour it into a transparent glass electronic universal pulling machine the size of a finger belly to repair the glass bottle. So far, the preliminary treatment of the sample has been completed. Put the glass bottle into the high performance liquid chromatography, and the instrument can automatically analyze whether it contains melamine at a glance. It took about one and a half hours from the preparation of samples to the final results

million yuan equipment

strict inspection of clenbuterol

"to detect the content of clenbuterol in meat products, it is much more complicated than the processing of meat products." In food testing, Xiao Luo, who is responsible for the detection of clenbuterol, said to avoid tissue changes caused by heat. The detection of each meat product requires 20 different reagents and materials. There are 9 kinds of experimental instruments used, and the total value of the instruments is millions of yuan. It takes at least 30 detection links to reach a conclusion, and this process generally takes 24 hours to complete

for the detection of clenbuterol, the preliminary extraction and purification of samples are similar to the detection of melamine, which is also divided into four main steps: sample weighing, extraction, purification and computer operation. However, the content of clenbuterol in meat products is very low, so the sensitivity of detection instruments is very high. Xiao Luo pointed to an instrument and said, "this instrument is one of the most expensive equipment in the food testing center, worth 2.3 million yuan. It is called high performance liquid chromatography tandem mass spectrometry. It can detect even 0.5 micrograms of clenbuterol per kilogram in meat products. It is like filling a swimming pool 50 meters long, 20 meters wide and 2 meters high with water, then pouring 1 gram of clenbuterol and fully mixing it. This instrument can detect such a low content."

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