How to check whether food packaging bags are qualified

Packaging bags, as we all know, are packaged properly for everything we buy. Do you know if the quality of the packaging bags is qualified?
1. The appearance shall be free from defects such as bubbles, perforations, water marks, blisters, poor plasticization, and fish eye blockages that hinder use. The deviation of specification width, length, and thickness should be within the specified deviation range.
2. The physical and mechanical properties include tensile strength and elongation at break, which reflect the ability of the product to withstand tension during use. If this item is not qualified, food packaging bags (films) are prone to cracking and damage during use.
3. The hygiene performance includes evaporation residue (acetic acid, ethanol, n-hexane), potassium permanganate consumption, heavy metals, and decolorization test. Evaporation residue reflects the possibility of food packaging bags releasing residue and heavy metals when encountering liquids such as vinegar, wine, and oil during use. Residues and heavy metals can have adverse effects on human health, and in addition, residue can directly affect the color, aroma, taste, and other edible qualities of food.
4. The degradation performance can be divided into photodegradation type, biodegradation type, and environmental degradation type based on the degradation type of the product. Degradation performance reflects the ability of a product to be accepted by the environment after being discarded. If the degradation performance is good, the bag (film) will break, differentiate, and degrade on its own under the combined action of light and microorganisms, ultimately becoming debris and accepted by the natural environment; If the biodegradability is poor, it will not be accepted by the environment, resulting in "white pollution".