2 Charles endoplasmic. For glass packaging products, its contents can be observed bump is complete, no foreign body, no turbidity. Normal products have a certain degree of vacuum, knock caps have crisp sound, if there is no vacuum, there is a big possibility that product quality problems.
3 anti-"fat listen." Shape changes do not buy the product, when canned food is microbial contamination, loss of food value, they often produce products "fat listen" phenomenon, namely overpack volume increases.
4 election genuine. Consumers should be at the mall to buy reputable main producing areas of informal enterprises or products have a certain scale production of the product, try not to buy products listed on the mall price reduction treatment.