Common foods such as meat, fish, vegetables and fruits can be canned. Canned food is mainly put into empty cans, degassed and sealed, and then heated and sterilized to achieve the purpose of preservation. Therefore, when the sterilization or sealing process is incomplete, canned food is easy to deteriorate and cannot be eaten.
When buying canned food, you should pay attention to the following items:
First, whether the tank type is normal. If canned food is found to have swelling, bulging bottle cap, elastic can or concave can, don't buy it, because the contents of such canned food may have undergone biological or chemical changes and are not suitable for eating.
Second, whether there is rust or scratches. Rusting of canned food may cause perforation of canned food, which makes it easy for microorganisms to enter and make food corrupt. Canned cans with scratches, twisted seams or depressions may be hit and scratched during handling or storage. In order to ensure the quality and safety, it is best not to buy this kind of canned food.
Third, whether the cans are tightly sealed. Is there any juice coming out? Pick up the can and shake it gently. If there is juice flowing out, the seal is not tight. If the seal is not tight, microorganisms can easily get in and out, which will pollute the contents. Don't buy this canned food.
Fourth, additives. The labels of some canned foods will indicate that some additives have been added to canned foods. As long as it meets the requirements, consumers can eat it with confidence, because the main purpose of adding additives is to maintain the nutritional value, flavor and appearance of food. As long as it is used properly, it will not cause harm to the human body.
5. Production date and shelf life. Production date is not the only index to judge the quality of canned food, because the quality of canned food is also closely related to various environmental factors during storage. But cans with good sealing conditions can be kept for one or two years. Some cans will also be marked with a shelf life. Don't buy it if it has expired or is not clearly marked.
6. Pay attention to canned fruits and vegetables in glass bottles. The iron cover should be tight and stainless, the shape of the contents should be complete, and the soup should be clear and transparent.