Food safety has always affected the "nerves" of most people. It happens from time to time that foreign bodies are eaten in catering, and it also happens that foreign bodies are eaten in finished products. The author has learned that in the production and processing of food, metal foreign bodies are often mixed into the product due to equipment wear, manual error, or poor quality of machinery and equipment. The mixing of these metals into food not only affects the quality and safety of products, but may also harm the vital interests of consumers. Therefore, in food processing, strengthening the detection and removal of metals is of great significance for ensuring food quality and safety. Among them, the metal detectors machine plays an important role in the metal removal process, so that foreign objects in food packaging "have nowhere to escape".

　 Metal detectors machine is a metal detection device, which is composed of a metal detector and an automatic rejection device, of which the detector is the core part. The system can use the alarm signal to drive the automatic rejection device, etc., so as to exclude metal impurities from the production line.

　　 The author understands that the metal detectors are divided by the conveying method of the detected items. Usually, the metal detector is divided into: channel type, falling type and pipeline type. At present, the most common metal detectors machine on the market is a channel conveying type, and the channel of the probe is square. Generally, it is equipped with a conveyor belt mechanism, with an automatic rejection device, or provides an alarm signal. When the food on the conveyor belt passes through the probe, once it contains metal, it will automatically reject or stop conveying. The instrument is mainly aimed at online detection of finished and semi-finished products, and provides the final detection before shipment. For example: boxed food, bagged food, etc.

　　Experts introduced that due to the current pulsation and current filtering, the metal detectors machine has certain restrictions on the conveying speed of the detected items. If the conveying speed exceeds a reasonable range, the sensitivity of the detector will decrease. It is also affected by changes in temperature, product size, humidity, etc. In addition, spherical metal objects are also the most difficult to detect for metal detectors machines. In order to ensure the sensitivity of detection, a suitable metal detector must be selected to suit the corresponding product being detected. In general, the detection range should be kept as small as possible. For products with good high frequency inductance, the detector channel size should match the product size.

　　As consumers and the country pay more and more attention to food safety, the food processing industry must not be indifferent to the production process and the quality and safety of the final product. Therefore, it is necessary to detect and supervise foreign matter in food. The author has learned that the metal detector is accurate in detection, easy to remove and install, and it is lightweight, which saves production space to the greatest extent and satisfies customers who require equipment space.

　　 It is understood that many companies install metal detectors machines at the end of the production line to ensure the quality and safety of the products. In fact, it is not the case. Earlier detection of metal objects will be more valuable, because what is wasted is only low-priced ingredients, not packaged finished products. In which part of the food processing, the specific installation needs to be selected according to the company's own situation, or follow the manufacturer's installation suggestions. For example, in the production of biscuits, most companies usually install detectors before the dough is formed into the drum. In this case, although the patterned brass rollers and forming rollers are easy to scratch the product, they avoid the danger of secondary "scratches" caused by metal impurities.

　　 We know that even people who are cautious can sometimes choke on eating, drinking water may choke, and there are many unexpected things that are difficult to grasp. What's more, food processing needs to go through multiple links, involving multiple equipment and manual operations. It is not ruled out that metal foreign objects, such as metal tags, metal fragments generated by milling machines, powdered material mesh wires, etc., are entered into the food. Using metal detectors machine, it is difficult for other detection equipment to detect accurately, otherwise it will enter the food.

At present, my country's metal detectors machine are mostly based on imported technology. Although domestically produced metal detectors meet the testing standards of some products, the sensitivity is not high enough, and the overall performance is not stable enough to ensure the accuracy of the product to remove metal foreign bodies. . For this reason, the author believes that domestic testing instrument manufacturers still need to continuously cultivate themselves, strengthen independent research and development capabilities, break the bottleneck of relying on imported technology, and realize the "Made in China" metal detectors, making the industry move towards "Made in China 2025". .