Agricultural products mesh bags shopping guide: breathable moisture-proof, to enhance the effect of fruit and vegetable freshness.
In the circulation of agricultural products, mesh bags as the core carrier of fruit and vegetable packaging, its performance directly affects the freshness of products and transportation loss rate. As a deep-rooted mesh bag industry for 20 years in charge of the production enterprise, I am well aware of the seemingly simple mesh bag behind the hidden technology doorway. This article will combine industry experience, from breathability, moisture resistance, material selection and other dimensions, to provide practical guidance for agricultural practitioners to buy.
First, breathability: the key parameter in determining the respiration of fruits and vegetables
Fruits and vegetables after picking is still a “living body”, need to maintain metabolism through respiration. The breathability of the mesh bag is directly related to the respiratory efficiency of fruits and vegetables and the risk of corruption.
Selection points:
Mesh bags density and aperture ratio:
Mesh aperture is too small (e.g. <3mm) will easily lead to insufficient air permeability, while too large aperture (e.g. >8mm) may damage the skin of fruits and vegetables. It is recommended to choose according to the type of fruits and vegetables:
Leafy vegetables (e.g. spinach, celery): aperture diameter of 4-5mm, density 16 × 16 mesh
Roots and tubers (e.g. potatoes, sweet potatoes): aperture diameter 6-8mm, density 12 x 12 mesh
Difference in weaving process:
Flat weaving process uniform breathability but lower strength, suitable for short-distance transportation; stranded weaving process strong tensile resistance, suitable for long-distance transportation of fruits and vegetables.
Second, the mesh bag moisture performance: the first line of defense to block the growth of mold and mildew
Humidity is the core factor leading to the decay of agricultural products. The moisture-proof property of mesh bag needs to balance the double demand of “blocking water vapor” and “discharging condensation”.
Technical solutions:
Material modification technology:
Using polypropylene (PP) and polyethylene (PE) blends, by adding hydrophobic particles (e.g., silicone), a waterproof layer can be formed on the surface of the fiber, and the measured moisture-proof rate is increased by 40%.
Structure optimization design:
Double-layer composite structure mesh bag (outer high-density moisture-proof, inner layer of breathable) for high humidity environment (such as shipping exports), the cost of a single-layer bag increased by 15% -20%, but can be controlled at a mold rate of less than 3%.
Third, the mesh bags material selection of the three major misconceptions and the truth
Myth 1: “Brand new material = quality bags”
Recycled material is not absolutely inferior, after strict screening of food-grade recycled PP material (ash ≤ 0.1%) in the cost reduction of 30% at the same time, can still meet the safety standards.
Myth 2: “The higher the weight, the more durable”
Grammage (e.g. 80g/㎡) needs to match the warp and weft density. High grams of low-density bags are easy to deform, it is recommended to choose grams of error ≤ 5%, warp and weft tension ≥ 8N balanced products.
Myth 3: “The color does not affect the function.”
White bags with high transmittance will accelerate the sprouting of potatoes and other tubers; it is recommended to use black or green bags for roots and tubers, and light-colored bags with transmittance > 70% for leafy vegetables.
Fourth, scenario-based shopping suggestions
Cold chain transportation scenario:
Choose anticondensation coated bags (surface adhesion ≥4B level) with antifreeze masterbatch (cold-resistant -25℃) to avoid low-temperature brittleness.
E-commerce small package:
Recommend 300×450mm specification degradable PLA bags, the degradation cycle can be controlled in 180-240 days, in line with environmental policy requirements.
Mesh bag export standard verification:
EU REACH certification needs to focus on 16 harmful substances testing, the U.S. FDA standards focus on migration indicators (≤ 0.01mg/kg).
V. Quality self-test methods
Procurement of three mesh bags can be quickly tested:
Combustion test: pure PP material burning candle flavor, no black smoke; mixed with recycled material bags will produce pungent odor when burning.
Moisture permeability test: take the bag piece covered with hot water cup, high-quality moisture-proof bags in 5 minutes without obvious water vapor condensation.
Tensile test: loaded with 5 times the nominal weight of the sandbag, hanging for 1 hour without rupture is qualified.
