When it comes to canned food, many people associate it with "more preservatives" due to its long shelf life and ready to eat characteristics, and even believe that it is not as healthy as fresh ingredients. Indeed, canned food often has a longer shelf life, even up to three to five years, which has led many people to label it as "junk food". But is that really the case? Actually, canned food has been misunderstood. Canned food not only preserves the nutritional value of ingredients while extending their shelf life, but in some cases, it even has advantages over fresh food. And its "preservation secret" does not rely on preservatives, but on unique processing techniques and sealing technology. China has been the world's largest producer and exporter of canned food for many years, accounting for about a quarter of the global production. However, various misunderstandings about canned food still exist. Today, let's uncover the truth and give a fair evaluation. Canned food really doesn't have "preservatives" because there is no need for GB 2760-2024 "National Food Safety Standard for the Use of Food Additives", which officially came into effect on February 8, 2025. It clearly stipulates that preservatives cannot be used in canned food. This policy not only marks a technological leap in China's food industry, but also breaks the long-standing misunderstanding of people's dependence on preservatives in canned food. According to the "Classification and Codes of National Economic Industries" formulated by the National Bureau of Statistics, canned products are mainly divided into canned meat and poultry, canned aquatic products, canned fruits and vegetables, and other canned foods. They all have one thing in common, which is a long shelf life, mostly 2-3 years. Actually, this is not surprising, as canned food was originally invented to extend the shelf life of food. Nowadays, with the development of technology, the production and processing of canned goods are becoming more and more modern. The secret of long-lasting preservation without the need for preservatives is hidden in the production process. According to GB 7098-2015 "National Food Safety Standard Canned Food", canned food is a commercially sterile canned food made from fruits, vegetables, edible fungi, livestock and poultry meat, aquatic animals, and other raw materials through processing, canning, sealing, heating and sterilization. The semi-finished products sealed in cans must be sterilized within 2 hours. The current mainstream method is thermal sterilization, which adjusts the time and temperature to achieve commercial sterility while maximizing the retention of the nutritional components of the food. Generally, there are two types of sterilization: low-temperature sterilization and high-temperature sterilization. ·Low temperature sterilization is carried out at 80-100 ℃, also known as atmospheric pressure sterilization, for 10-30 minutes. It is suitable for canned fruits and some canned vegetables with high acid content (pH below 4.6). For example, canned peaches, canned pineapples, canned citrus fruits, etc. can keep the flesh intact and have a taste similar to fresh fruits; Canned pickles and canned tomato sauce also require low-temperature sterilization. ·High temperature sterilization is carried out at 105~121 ℃, also known as high-pressure sterilization, for 20~90 minutes. It is suitable for meat, aquatic products, and most canned vegetables with low acid content (pH above 4.6) and non acidic properties. For example, canned lunch meat, canned Braised pork belly, canned sardine, canned sweet corn, canned green beans, canned chickpeas, etc. are also sterilized at high temperature, which can soften the texture of food materials while retaining complete dietary fiber. With the development of food processing technology, new technologies such as modified atmosphere sterilization and microwave sterilization have emerged. The sterilization time is short, the effect is good, and it is more conducive to preserving the color, flavor, and nutrition of the food itself. After such sterilization treatment, there is no room for microorganisms to survive. After high-temperature sterilization, it needs to be cooled to below 40 ℃. At this time, negative pressure will form inside the container, and the lid will be sealed more tightly, making it difficult to open. Throughout the entire process, there are no microorganisms surviving inside the can, and external microorganisms cannot enter, so there is no need for preservatives. Canned food can also be very nutritious. Scientific comparison overturns the cognition that canned food will not spoil even after being stored for a long time, to the point where some people believe that it is not as nutritious as fresh food and has little nutritional value. The fact may overturn many people's cognition. Within the same storage time, food stored in cans may be more helpful in preserving some nutrients and reducing the loss of some nutrients than fresh food stored at room temperature. 1. Canned fruits and vegetables - more fresh and nutritious than stored at room temperature. Fresh fruits and vegetables have the highest nutritional value when they are just ripe and not picked. Once they are picked and stored and transported for a long time, the nutrients will gradually be lost. For example, green peas lose 51% of their vitamin C 24-48 hours after picking. Canned food is mostly processed directly from fresh food ingredients, and the potassium, calcium, and magnesium content of fruits and vegetables does not decrease during the processing, and dietary fiber is also preserved. Although heat sensitive vitamins C and B are lost significantly, only a small portion of the nutrients are lost during transportation and storage, and further loss of vitamin C often does not exceed 15%. The University of Illinois in the United States has conducted a comprehensive comparison of the nutritional content of fresh and canned fruits and vegetables. Although high temperature heating during canning can cause some loss of vitamin C and vitamin B, the vacuum sealing of canned fruits isolates oxygen, resulting in significantly less nutrient loss than fresh fruits stored at room temperature or frozen fruits and vegetables. In addition, canned food is generally rarely further processed, resulting in less nutrient loss. Most fresh vegetables require further cooking before consumption, which can result in a further loss of 15% to 55% of vitamin C and 11% to 66% of vitamin B1 during the cooking process. The canned citrus fruits we usually eat have been found to have a vitamin C content of 10-47 milligrams per 100 grams, while fresh citrus fruits typically have a vitamin C content of 20-40 milligrams per 100 grams, and there is not much loss in comparison. There is also canned sweet corn that everyone loves to eat. A study has found that after heating at 15 ℃ for 25 minutes, compared with fresh sweet corn, although vitamin C is lost by 25%, the total antioxidant activity of sweet corn is significantly increased by 44%. Even more surprisingly, the content of ferulic acid (an antioxidant component) increased by 550%, and the total phenolic substances also increased by 54%. Research has also found that canned foods are often richer in carotenoids than fresh foods, and may even increase their bioavailability, with carotenoids being an important source of vitamin A for the human body. Compared with fresh tomatoes, canned tomatoes have an increase in lycopene and a higher content of beta carotene, which may be 50% higher than fresh tomatoes; According to the US Department of Agriculture's nutrition database, canned pumpkins also have higher levels of beta carotene and vitamin A than fresh pumpkins. The canning process has also been proven to increase the protein (>7%) and dietary fiber (>5%) content of various bean varieties, while reducing the amount of lectins. In addition, some canned fruits are added with vitamin C to prevent oxidation and extend shelf life. For example, the canned yellow peach shown in the picture may have an advantage in vitamin C content compared to fresh yellow peaches. 2. The high-temperature sterilization process of canned meat may cause loss of the heat sensitive vitamin B group in the meat, but it will not have a significant impact on protein and n-3 series unsaturated fatty acids. The following table shows a nutritional comparison between fresh tuna and canned tuna. Currently, most canned tuna on the market are yellowfin tuna and mackerel tuna. In addition, canned fish also retains a higher amount of vitamin D. There are few foods rich in vitamin D, but mackerel is a common food with a relatively high vitamin D content of 16.1 micrograms per 100 grams. Even canned mackerel contains 7.3 micrograms per 100 grams. Eating 100 grams (about 1 palm) can meet 73% of the average adult's vitamin D requirement. A study in the United States shows that people who regularly eat canned food (≥ 6 cans/week) have a richer food intake, such as fruits, vegetables, and protein rich foods, compared to those who do not regularly eat canned food (≤ 2 cans/week), and also consume higher amounts of potassium, calcium, dietary fiber, etc. Therefore, in addition to fresh food, nutrient rich canned foods can also improve nutrient intake and overall dietary quality. So, canned food is not without nutrients, don't misunderstand it anymore. When it is difficult to consume sufficient fresh food, canned food is a good choice as it helps improve the quality of diet and enhance nutrition. Eating canned food in this way is more reassuring. In the "National Basic Version of Family Emergency Material Reserve Suggestions List" and "Family Emergency Plan" released by the Ministry of Emergency Management of the People's Republic of China, canned food is recommended as a family emergency reserve food. If you want to eat canned food healthily, you should first choose food produced by reputable manufacturers, and familiar brands are better. In addition to looking at the shelf life, it is also important to check the appearance of the can and avoid choosing cans that are bulky, rusty, poorly sealed, or leaking. When choosing low-fat, low sodium, and low sugar products, it is also important to check the sodium, fat, and sugar content in the nutrition chart and choose a product that is relatively low-fat, low sodium, and low sugar. For example, canned tuna, try to choose water immersion technology and avoid oil immersion technology. However, in oil immersed canned goods, olive oil can also be considered as a supplement to oleic acid, which is beneficial for cardiovascular health. According to the requirements of the "General Rules for Nutritional Labeling of Prepackaged Foods": · Low salt: Sodium content ≤ 120mg/100g (solid) or 100ml (liquid) · Low sugar: Carbohydrates (sugar) ≤ 5g/100g (solid) or 100ml (liquid) · Low fat: Fat content ≤ 3g/100g (or 1.5g/100ml). 03 Drink less canned soup with high salt, sugar, and fat content. If you like, occasionally satisfy your cravings and do not eat too often. When eating canned fruits, it is advisable to drink less soup and reduce sugar intake, which can also prevent large fluctuations in blood sugar levels. After opening, canned food should be consumed as soon as possible. Once opened, it no longer has the advantage of being sealed and isolated from bacteria, and it is also prone to spoilage like regular food. It is best to consume it as soon as possible to avoid secondary storage. Canned food is not without nutrients and generally does not contain preservatives. In today's fast-paced life, it is a great helper to help us save time and balance nutrition. High quality canned food with low salt, low fat, and low sugar is still a great food! (New Society)