(1) Look at the trademark. When buying packaging bags, you must carefully observe the packaging box and the paper bags in the box to see if there are trademarks. Fruit bags with trademarks are generally of high quality and guaranteed. The packaging box should have the factory name, address, contact number, and paper bag. Specifications and quantities, etc.

(2) Look at the hydrophobicity of the outer bag. High-quality paper bags must undergo hydrophobic treatment and require a certain degree of hydrophobicity. The identification method is to pour some water on the outer bag, and then tilt the bag. If the water flows away quickly, the outer bag does not stick or basically does not stick, indicating that the hydrophobic performance is good. This kind of fruit bag does not deform after rain and has good quality. On the contrary, fruit bags with poor hydrophobicity are also of poor quality.

(3) Looking at the wet strength of fruit packaging bags, the paper requirements for making fruit bags are pure wood pulp paper or paper with high wood pulp content. The fruit bag made of this kind of paper will not break when exposed to wind, rain and exposure. The identification method is to look at its wet strength. You can tear off a piece of the outer layer of the fruit bag, soak it in water for 1 to 2 hours, then take it out, and gently pull it outwards with both hands. Repeat several times. If it has a certain degree of flexibility and continuous pulling, it means that the wet strength is large, that is, pure wood pulp paper, or high wood pulp content, which can meet the requirements of qualified fruit bags. If it breaks with a slight pull, it indicates that the paper does not meet the requirements.

(4) Look at the light leakage of the fruit bag. Tear the fruit bag and observe it against the light or sunlight to see if the light transmission is uniform. Do not use uneven fruit bags with poor quality, otherwise the color of the fruit surface will be inconsistent and affect the viewing effect.

(5) To see if the fruit bag has faded, moisten the fruit bag with water, and smear it on white paper to see if there is any color loss. If the color fades, it will directly pollute the fruit surface in the future and even cause rust spots on the fruit surface and affect viewing.

(6) The wax for the inner bag of the waxy layer must be summer wax. The identification method is to put the inner bag in hot water at 60℃. If it does not melt, it is summer wax. High-quality fruit bags require uniform wax coating on the inner bag. The identification method is to use fire to observe the melting of wax.

(7) Look at the air permeability. Take a cup of boiling water and spread the paper bag flat on the cup. If water vapor emerges from the paper bag, the air permeability is good and the quality of the paper bag is high.

(8) Look at the vent hole on both sides of the vent hole to be symmetrical, the size is appropriate, and the drainage is unobstructed without water accumulation.

(9) The paper bag does not stick, degummed, and does not lose the tie. The tie is soft and hard, easy to close and easy to untie.