1. Look at the outer packaging: Observe whether the outer packaging is clean and tidy, whether the handwriting is clear, whether it is within the shelf life, and whether the food label is marked with the company's name, address, contact number and other information.

2. Observation of food quality: For products packaged in glass bottles, it can be observed whether the block shape of the contents is complete, no foreign matter, and no turbidity. The normal product has a certain degree of vacuum, and there is a crisp sound when the bottle cap is knocked. If there is no vacuum, the product is likely to have quality problems.

3. Prevent "fat tint": Do not buy products whose appearance has changed. When the canned food is contaminated by microorganisms and loses its edible value, the phenomenon of "fat tint" of the product often occurs, that is, the volume of the outer packaging increases.

4. Choose regular products: Consumers should try their best to buy products produced by regular enterprises or enterprises with a certain scale in the main product producing areas in reputable shopping malls, and try not to buy products that are listed in shopping malls for reduced prices.

5. Eat as soon as possible: After the canned food is opened, it is easy to cause a large number of microorganisms, causing the product to deteriorate and lose its edible value. Consumers are advised to try to finish the food at one time to prevent spoilage and food poisoning.