(1) Hidden dangers of packaging materials
At present, there are many food containers and packaging materials allowed in my country, and different types of materials may bring different safety hazards. Plastic is one of the most widely used food packaging materials. Its hazards mainly come from the toxic monomers and pyrolysates remaining in the product. Paper products are also a traditional food packaging material. The raw materials used in the production of food packaging paper may be unclean, and there may be pollution problems such as heavy metals, pesticide residues, and even recycled waste paper as raw materials, causing chemical residues and microbial pollution. Rubber products commonly used in food packaging materials may have potential hazards from synthetic rubber monomers or processing aids. In addition, toxic metal ions may precipitate from metal packaging materials, silicon dioxide may be dissolved from glass materials, and metal oxides may also be dissolved from ceramic glazes.
(2) Illegal addition of various processing aids in the production process
Irregular production of packaging materials or containers is also one of the main reasons for food safety hazards. At present, most food companies do not allow packaging companies to mark their products, which makes it impossible for consumers to identify the "place of origin" of the packaging. Since consumers cannot supervise, food companies often decide to purchase various processing aids based on whether the cost is low, which causes hidden food safety hazards. For example, plastics are high-molecular polymers, which are formed by polymerization of monomers and initiators under appropriate conditions. In order to improve the processing performance of the plastic and the use performance of the finished product, processing aids such as plasticizers, antistatic agents, smoothing agents, and heat stabilizers should be added in the finished product process. Plastic monomers and processing aids are low-molecular compounds. Under certain medium and temperature conditions, they will dissolve from the plastic and transfer to the food, thereby contaminating the food and causing harm to human health.
(3) Packaging and printing pollution
Ink is an indispensable basic material for packaging and printing, and it is also one of the main sources of food contamination. There are two types of traditional packaging printing inks: resin-based and solvent-based. When printing with these two inks, some harmful substances such as heavy metals, organic volatiles and solvent residues will be produced.
(4) Packaging testing standards
Therefore, the quality of food packaging bags in the flexible packaging industry, especially the hygienic quality, is directly related to the safety of packaged food. Therefore, it is necessary to ensure that the raw materials and additives used meet the quality requirements of the management system. It is necessary to improve and strictly implement the packaging film bag industry standards and national standards, strengthen inspection and supervision of food packaging, prevent unqualified food packaging from entering the market, strengthen management, and ensure the healthy development of the flexible packaging industry. Food packaging single film bag inspection items are mainly divided into the following categories:
1. The appearance is free of defects such as bubbles, perforations, water lines, bursts, poor plasticization, and fish-eye blocks.
2. The physical and mechanical properties include tensile strength and elongation at break, which reflect the tensile ability of the product during use. If this item is unqualified, the food packaging bag will be easily broken and damaged during use.
3. Tensile strength and elongation at break, it reflects the ability of the product to withstand tension during use. If this item is unqualified, the food packaging bag is easily broken and damaged during use.
4. Gas barrier properties such as gas permeability (oxygen permeability, moisture permeability, air permeability).
5. Oil resistance index, heat resistance, cold resistance, medium resistance; these indicators reflect the reliability of food packaging bags to protect the inner packaging.
