The quality of a food packaging bag can directly affect the product, and it accompanies the whole process of food production, circulation and use. So how to judge whether the food packaging bag is qualified? 11. The appearance of food packaging bags must not have defects such as air bubbles, perforations, water marks, violent tendons, poor plasticization, and fish-eye stiffness that are harmful to use. The specification width, length, and thickness deviations should be within the specified deviation range. 21. The physical and mechanical properties in the process of making food packaging bags include tensile strength and elongation at break, which reflect the ability of the product to withstand stretching during use. If this item is unqualified, the food packaging bag (film) ) are prone to breakage and damage. 3Hygienic performance including evaporation residue (acetic acid, ethanol, n-hexane), potassium permanganate consumption, heavy metals, decolorization test. Evaporation residues reflect the possibility of precipitation of residues and heavy metals when food packaging bags encounter liquids such as vinegar, wine, and oil during use. Residues and heavy metals will have adverse effects on human health. In addition, residues will directly affect the color and aroma of food. , taste and other edible quality. Therefore, companies that customize food packaging bags must conduct on-site inspections of manufacturers to ensure safety and hygiene before placing orders. 4, Degradation performance According to the different degradation types of the product, it can be divided into photodegradation type, biodegradation type and environmental degradation type. The degradation performance reflects the ability of the product to be accepted by the environment after being used and discarded. If the degradation performance is good, the bag (film) will break, decompose and degrade by itself under the combined action of light and microorganisms, and eventually become debris, which is the natural environment. Accepted; if the degradability is not good, it will not be accepted by the environment, thus forming”White pollution”.