1. Check the outer packaging: Check whether the outer packaging is clean and tidy, whether the handwriting and printing are clear, whether it is within the shelf life, and whether the food label indicates the name, address, contact phone number, and other information of the enterprise.

2. Observing food quality: For products packaged in glass bottles, it is possible to observe whether the shape of the contents is complete, without foreign objects or turbidity. Normal products have a certain degree of vacuum, and there is a crisp sound when knocking on the bottle cap. If there is no vacuum, there is a high possibility of quality problems in the product.

3. Prevention of "fat listening": Do not purchase products with changes in appearance. When canned food is contaminated by microorganisms and loses its edible value, it often leads to the phenomenon of "fat listening" of the product, which means the outer packaging volume increases.

4. Choose legitimate products: Consumers should try to purchase products produced by legitimate enterprises or enterprises with a certain scale in their main production areas in reputable shopping malls, and try not to purchase products that are listed and discounted in the mall.

5. Early consumption: After opening the lid of canned food, it is easy to cause a large number of microorganisms to multiply, causing the product to spoil and lose its edible value. It is recommended that consumers consume it all at once to prevent spoilage and food poisoning.