Because during contact with the contents, small molecular substances from the plastic may migrate outward into the food, potentially affecting the health of consumers. If the total migration amount of the sample exceeds 10 mg/d㎡, the product is deemed non-compliant.
(In terms of hygiene performance)
I. Sensory Requirements
Sensory requirements involve using one's own sensory organs as the testing method to evaluate and determine the quality characteristics of PET bottles.
Xiaomin Talks Testing:
Check the color of the PET bottle to ensure it’s normal, and look for any unusual odors, mold spots, or other contaminants. After soaking, also verify whether there’s any discoloration or lingering strange smells.
II. Total Migration Amount
The total migration test involves simulating the contact between food and packaging materials, allowing migratable substances from the packaging to transfer into a food simulant. The total amount of these migrants is then determined through an evaporation-drying-weighing process.
Xiaomin Talks Testing:
Because during contact with the contents, small molecular substances from the plastic may migrate outward into the food, potentially affecting the health of consumers. If the total migration amount of the sample exceeds 10 mg/d㎡, the product is deemed不合格 (non-compliant).
3. Potassium Permanganate
The potassium permanganate consumption refers to the amount of substances in PET material that can be oxidized by potassium permanganate and migrate into the soaking liquid. Most of the substances oxidized by potassium permanganate are organic compounds that have migrated out, including polymer monomers, olefins, and other similar materials.
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This test determines whether PET materials contain soluble organic substances (such as polymer olefins, dimers, trimers, and other low-molecular-weight polymers). Since these soluble organic compounds can enter the human body through liquids and potentially pose health risks to consumers, China has established strict regulatory limits for food-contact materials, ensuring that such substances do not exceed specified thresholds.
10 mg/kg.
4. Heavy Metals (expressed as Pb)
Heavy metals pose certain risks to human health and the environment, which is why PET bottles (food-contact plastics) are required to undergo testing for heavy metals—specifically measured as Pb.
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This test determines whether PET bottles contain excessive levels of heavy metals, with the requirement that such levels must not exceed.
1 mg/kg.
The decolorization test involves checking whether the sample’s soaking solution picks up any color, as well as testing if the packaging material or container surface loses its original color by wiping it with cotton soaked in solvents like cold-pressed oil or ethanol—ensuring no color transfers to the cotton.
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This test can determine whether there is a risk of migration for the coloring agents or ink in the printed layer.
6. Antimony Migration Amount
Antimony (symbol Sb) is typically a silvery-white metallic element, hard yet brittle. It is an important semiconductor material and a key component in infrared detectors.
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Traditional PET bottle manufacturing uses antimony as a catalyst in polyester-based plastic products. During the high-temperature filling process of PET bottles, heavy metal antimony can easily leach out of the PET material and migrate into the liquid, potentially posing health risks to humans. According to the GB4806.6—2016 standard, plastic resins intended for food contact must have an antimony content of no more than 0.04 mg/kg to be considered compliant.
7. Migration Amount of Isophthalic Acid
Isophthalic acid is also known as m-phthalic acid or 1,3-benzenedicarboxylic acid.
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Isophthalic acid (IPA) is used in the production of alkyd resins, unsaturated polyester resins, and other polymers and plasticizers. It is also employed in manufacturing film developers for motion pictures, as well as coatings, polyester fiber dyeing modifiers, and even in pharmaceutical applications. IPA enhances the strength, toughness, fatigue resistance, and corrosion resistance of resin materials.
However, it can irritate the eyes and upper respiratory tract, and at high concentrations, it may exert an anesthetic effect on the central nervous system. According to the GB4806.6—2016 standard, food-contact plastic resins must have an isophthalic acid content of less than 5 mg/kg to be considered compliant.
8. Migration Amount of Terephthalic Acid
Terephthalic acid, with the molecular formula C8H6O4, is an organic compound and the most widely produced dicarboxylic acid.
Xiaomin Talks Testing: Terephthalic acid is irritating to the eyes, skin, mucous membranes, and upper respiratory tract. Its applications are relatively concentrated—over 90% of the world’s terephthalic acid is used to produce polyethylene terephthalate (commonly known as polyester resin). According to the GB4806.6—2016 standard, plastic resins intended for food contact must have a terephthalic acid content of no more than 7.5 mg/kg to be considered compliant.
9. Ethylene Glycol
Ethylene glycol, also known as glycol or 1,2-ethanediol, is commonly abbreviated as EG. Its chemical formula is (CH₂OH)₂, making it the simplest diol.
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Ethylene glycol is a colorless, odorless, sweet-tasting liquid with low toxicity. It is miscible with water and acetone.
It dissolves, but with lower solubility in ethers. According to the GB4806.6—2016 standard, plastic resins intended for food contact are considered compliant if their ethylene glycol content is below 30 mg/kg.
