When it comes to food safety, there is a problem that cannot be ignored. That is the problem of food packaging. Hygienic quality problems occur in food packaging. Printing ink is one of the key factors.
How benzene poses a threat to health Many colorful food products are printed on the packaging. However, most of the printed inks contain benzene that is harmful to the human body. In a special spot check in 2005, the national quality supervisory inspectors randomly identified seven plastic color printing companies that produced composite food packaging films. Each company took two samples for inspection. One was sent to the Gansu Product Quality Inspection Center in Lanzhou City and the other to the National Center for Quality Inspection of Packaging Products in Chengdu. Five of the seven samples were found to have excessive benzene residues, which involved the packaging of beef jerky, milk powder, confectionery, dried bean curd, and potato chips. One of the most serious is a powdered milk bag produced by Gansu Senjie Packaging Co., Ltd., and the benzene residue actually exceeds the national standard. If it is put into production, it is equivalent to putting milk powder into a highly toxic pocket.
In order to quickly print thick inks onto plastic films used for food packaging, companies need to add a mixed solvent that dilutes and promotes drying to the ink when producing packaging bags. Because the ink used in our country's ink system is itself benzene-containing, it can only be diluted with a mixed solvent containing toluene. However, due to the different sources of toluene on the market, the purity and price are much different. If the company uses low-purity, cheap toluene in the production of food packaging bags, then the problem of benzene residue will be even more serious. Toluene, butanone, ethyl acetate, isopropyl alcohol are all basic raw materials for blending mixed solvents. Excessive amounts of these substances will undoubtedly affect the safety of packaged foods.
Regarding the hazards of benzene residues, the related companies mostly know very clearly, but the methods for controlling benzene residues vary greatly among companies. Larger companies usually rely on high-speed printing equipment and powerful exhaust systems to reduce benzene residue, but such equipment must be invested in millions or even tens of millions of yuan to be equipped. In addition to adding exhaust fans to the workshop, small businesses with relatively rudimentary equipment can only rely on baking in such a high-temperature curing plant to reduce benzene residues.
Because benzene occurs in ink thinners and binders, if the manufacturer does not allow enough time for the benzene to evaporate during the production process, benzene will remain in the finished product. After a certain amount of benzene, it will affect human health. threatening. The "benzene content" of some food packaging bags circulating on the market far exceeds the standards set by the state, which poses a direct threat to human health.
The harm of ink composition to human body
Organic solvents dissolve many natural resins and synthetic resins and are an important component of various inks. Some of these ingredients can damage the human body and subcutaneous fat. Long-term exposure can cause dry, rough skin. If it penetrates into the skin or blood vessels, it will endanger human blood cells and hematopoietic function. Inhaled into the airway, bronchus, lungs or through the blood vessels, lymphatic vessels spread to other organs, and may even cause chronic body poisoning. Some inks contain the toxicity of heavy metal ions. Pigments and dyes contain carcinogenic ingredients that are harmful to human health.
Composite packaging materials used in printing a large number of inks, organic solvents and adhesives, etc., these accessories with. Although there is no direct contact with food, some toxic substances will migrate into the food during the food packaging and storage process, endangering people's health. Ethanol, isopropyl alcohol, butanol, propanol, butanone, ethyl acetate, butyl acetate, toluene, xylene and other organic solvents are often used in printing inks. Although most of these solvents can be removed by drying, residual solvents can migrate into foods and harm the human body.
Phenanthrene is a product of coal tar distillation or petroleum cracking. Benzene can cause chronic poisoning. It mainly causes damage to the nervous system and hematopoietic system. It manifests itself as headache, dizziness, insomnia, leukopenia, thrombocytopenia, and bleeding tendency. These damages occur more slowly and do not occur in the short term and are easily overlooked by consumers. Therefore, the ink cannot be in direct contact with the food. Now most food packaging bags are printed in such a way that the pattern is printed on the plastic bag and a layer of plastic is attached to it, ie the ink is enclosed between the two plastic layers so that the food is not easily contaminated. However, consumers still have to be vigilant. Plastic bags that can be broken by hand can be rejected. Benzene is a highly volatile substance that can be easily released into the atmosphere during the printing process to pollute the environment
Gravure inks use more VOC as a solvent. Long-term exposure to high concentrations of VOCs will cause significant damage to the human body, especially the nervous system. VOCs also react photochemically with nitrogen oxides in the air to produce ozone and fumes. At present, the domestic gravure printing technology contains printing ink containing formaldehyde, which is harmful to the human body, but it is still not banned. At present, there may be only two layers of plastic between some pickled foods and harmful chemicals such as formaldehyde.
Because soft packaging is mostly composite materials, glue must be used in composite materials, there are many impurities in aromatic and aliphatic glues, and high-temperature cooking environments are often encountered during food manufacturing. Under these circumstances, these harmful substances will be released. , The formation of harmful substances GDI (isocyanate) and infiltration of food.
Strengthen the management of food packaging
Countries such as Europe and the United States have not allowed the use of raw materials containing benzene and heavy metals in food packaging. The Japanese government has also stipulated that food packaging materials must not contain benzene b three years ago. At present, China has only made requirements for the internal packaging of food, but only Recommended standards. The national standard GB/T 10005-1998, which was implemented on February 1, 1999, specifies that the total amount of solvent in the composite film and bag should be ≤ 10 mg/m 2 , with the benzene solvent being less than 3.0 mg/m 2 . For food packaging, its supervision is limited to size, appearance, strength, physical and mechanical properties, etc. It is rarely involved in the residual content of solvents and other harmful substances.
There are no mandatory standards, no effective supervision, no unified deployment process, and no specific restrictions. These factors have led to excessive benzene residues in the company's products becoming a relatively common phenomenon. At present, the National Printing Ink Standardization Technical Committee has submitted relevant national departments and is planning to draft two mandatory standards to regulate the residual limit of ink solvents in food packaging.
The AQSIQ requires all local quality and technical supervision departments to inspect materials and printed crystals used for food packaging to prevent contaminated foods containing harmful substances. However, the cost of benzene testing is quite high, and a packaging costs more than 1,000 yuan. However, most of the packaging companies in China are small enterprises. The restrictions on capital and the fact that a large number of small and medium-sized enterprises will not test the residual benzene content will not have the ability to detect benzene content.
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