Pre made meals are not necessarily unhealthy, they are a convenient supplement to fast-paced life. As long as food information and production processes are clearly disclosed to ensure the right to know, most consumers can also accept it. On September 21st, the reporter learned from the State Administration for Market Regulation that the State Council Food Safety Office attaches great importance to the recently widely concerned topic of pre packaged meals. It has organized multiple departments to carefully study and accelerate the development of national standards for pre packaged meals, vigorously promote the use of pre packaged meals in the catering industry, and better safeguard consumers' right to know and choose. The reason why the topic of pre made meals has attracted widespread social attention is mainly due to consumers' concerns about their quality. Prefabricated dishes can be stored for more than a year, and a large amount of preservatives must be added. Frozen prefabricated dishes lose all their nutrients after heating. Recently, the topic of prefabricated dishes has remained hot, and rumors about their preservation effect and nutritional value have made many consumers concerned. In response to these questions, the reporter recently interviewed relevant experts to explore them for you. Preservation mainly relies on aseptic processing and freezing technology. Some netizens have suggested that the shelf life of pre made dishes far exceeds that of fresh ingredients, which is inevitably achieved by adding a large amount of preservatives. Regarding this, Professor Fan Zhihong from the School of Food Science and Nutritional Engineering at China Agricultural University believes that "the reason why pre packaged vegetables can be preserved for a long time mainly relies on technologies such as low-temperature freezing, without relying on preservatives. Extending the shelf life through preservatives is not the mainstream of modern food preservation technology, at most it can only be considered as a supplementary measure." She introduced that the main challenges in food preservation come from microbial proliferation and fat oxidation, and long shelf life foods mainly solve these two problems through the following two technologies. One is aseptic processing technology, which first kills microorganisms in food through thermal or non thermal sterilization methods, and then seals and packages the food in a sterile environment. From a technical perspective, aseptic processing technology is consistent with the preservation logic of canned food. This technology can kill microorganisms, isolate external microorganisms outside the packaging, and significantly reduce oxygen and inhibit fat oxidation through a sealed environment, allowing food to be stored at room temperature for six months to two years without adding preservatives. The second is low-temperature freezing technology, which means that pre made dishes are frozen and stored in a low-temperature environment below minus 18 degrees Celsius. At this temperature, microorganisms find it difficult to reproduce, and chemical reactions such as fat oxidation are significantly slowed down. This technology can preserve food for 1 to 2 years without the need for preservatives. A food science expert told reporters that through rapid freezing technology, the internal temperature of food can be quickly reduced to minus 18 degrees Celsius, forming small ice crystals inside. These small ice crystals can protect the organizational structure of the product and reduce nutrient loss. However, various ingredients and finished products that are preserved using low-temperature freezing technology require cold chain transportation. "Only in foods that cannot be fully sterilized and frozen at low temperature, can preservatives be used to assist in preservation, such as low sugar preserved fruit, low salt Pickled vegetables, salt reduced soy sauce and other foods that need to be stored at room temperature for a long time. ”Fan Zhihong emphasized that the preservation of qualified pre processed ingredients and pre made dishes produced by legitimate manufacturers relies on sterilization, sterilization processes, and quick freezing and freezing conditions, rather than preservatives. Nutrients are indeed lost, but not reset. Some netizens believe that pre made dishes undergo freezing, storage, reheating, and other processes, resulting in the loss of vitamins, minerals, and other nutrients in the ingredients. Non pre made dishes are safer and more nutritious. Regarding this, Fan Zhihong believes that "this is a typical cognitive misconception. The nutrition of pre made vegetables cannot be generalized, and their nutritional loss needs to be objectively viewed. Vegetables made on site may not necessarily have high nutritional value, depending on the quality of raw materials and cooking methods. Compared with long-term storage at room temperature, scientific refrigeration and freezing treatment can actually improve the preservation rate of some nutrients and reduce the content of nitrite." "Frozen fruits and vegetables are not" nutrient depressions ". Cryopreservation is currently the best method of food storage, which can maximize the preservation of food's nutrition and quality. ”The aforementioned experts in the field of food science said. Fan Zhihong gave an example that after being stored at room temperature for 3 days, the vitamin C content of broccoli and some green leafy vegetables will significantly decrease. In a controlled atmosphere cold storage at 1 degree Celsius, ingredients can be stored for two to three months with minimal loss of vitamin C content. If frozen, even if the ingredients are stored at minus 18 degrees Celsius for a year, the loss of vitamin C is relatively limited. From the perspective of processing and heating, there are category differences in the loss of nutrients in pre made dishes, and it is not "completely gone". Nutrients such as proteins and minerals have stable properties and will not be lost during freezing, heating, and other processes; Nutrients such as B vitamins that are easily destroyed may have a small loss, but this loss is not more severe than packaged ready to eat foods such as roasted chicken and pickled duck. Fan Zhihong further pointed out that in terms of nutrient intake, compared to vitamin loss, consumers need to pay more attention to the issues of salt infiltration and glycation products in pre packaged dishes with long shelf life. Regarding salt infiltration, she explained that some pre made dishes gradually absorb surface salt during long-term storage. This kind of infiltration is not conducive to salt control. For glycation products, she said that the sugar and protein in dishes not only react during cooking and heating, but also slowly react during long-term room temperature storage to produce glycation products. If a large amount of glycated products are consumed for a long time, it may accelerate human aging and increase the risk of chronic diseases. The above two points are nutritional details that consumers tend to overlook. Compared to that, when stored under freezing conditions, there are very few glycation reaction products. Fan Zhihong specifically reminds that if some fast food restaurants keep their freshly made dishes in a 60 degree Celsius warmer for a long time, the degree of vitamin loss and glycation reaction products may be much higher than those of frozen pre made dishes. From this, it can be seen that we cannot simply assume that 'non pre made dishes are safer and more nutritious'. The key lies in whether the storage method and processing procedures are safe and standardized, "she said. In Fan Zhihong's view, pre made meals are not necessarily unhealthy, they are a "convenient supplement" to fast-paced life. As long as food information and production processes are clearly disclosed to ensure the right to know, most consumers can also accept it. When selecting pre packaged dishes, attention should be paid to the "two tables". Qualified pre packaged dishes have safety guarantees, and consumers do not need to worry excessively. Consumers can pay close attention to the ingredient list and nutritional content list when selecting pre made food products. When viewing the ingredient list, priority should be given to selecting products with clear types of ingredients and low nutritional value ingredients such as oil, sugar, starch, and dextrin that rank lower. In the nutrition table, sodium content and fat content are important reference indicators, and it is recommended to prioritize pre made dishes with lower levels of both. Common pre made dishes on the market that mainly consist of meat, fish, and other ingredients, such as braised pork ribs and pan fried hairtail, may add a lot of salt, soy sauce, or oil during the production process to pursue flavor, resulting in high sodium and fat content. Long term intake of foods with high sodium content can increase the body's metabolic burden and be detrimental to blood pressure control. Consuming foods with high fat content can easily lead to excessive calorie intake, which in the long run may cause problems such as weight gain. Therefore, learning to check the ingredient list and nutrient composition list of pre made dishes is essential for eating healthier. (New Society)