When choosing packaging materials for frozen foods, the first step is to study the sensitive factors that affect the main components of frozen foods, especially nutrients such as fat, protein, and vitamins, including light, oxygen, temperature, microorganisms, and physical and mechanical factors. Then, according to the protection requirements of food content, transportation environment, etc., determine the type of packaging materials and the operation mode of packaging technology to achieve the purpose of protection function and appropriately extend the storage period.

1. Hygiene

From a safety point of view, our packaging materials, such as plastic bags, must meet food-grade standards. Due to the packaging and transportation process of frozen food, it is often difficult to ensure a continuous low temperature environment throughout the process, especially during the transfer and handling process, which may cause the temperature of the frozen food to rise significantly over a period of time. If the material is not qualified, it is easy to breed bacteria. The appearance of packaging made of recycled or industrial-grade materials is not much different from packaging made of food-grade materials, but due to the presence of excessive plasticizers and other substances, once used, it will cause great harm to human health.

2. Cold resistance

Frozen foods are usually stored and circulated at a temperature of -18°C or lower, especially for some frozen foods with trays. In the production process, the food is usually rapidly cooled together with the tray at a temperature below -30°C until the center temperature of the product is below -18°C, and then packaged. In the case of a sudden drop in temperature, the mechanical strength of the packaging material is also reduced, resulting in a fragile packaging material. In addition, frozen food is inevitably subject to various environmental hazards, such as shock, vibration and pressure, during transfer and transportation. In addition, frozen foods such as rice dumplings and dumplings are hard at low temperatures. It is easy to cause damage and cracking of packaging bags. This requires the packaging material to have good low temperature performance.

4. Heat seal strength

If the heat sealing strength of the packaging bag is insufficient or the sealing is false, a slight impact will cause the sealing point to crack; if the heat sealing temperature is too high, it is easy to cause damage to the heat sealing layer and weaken the material strength at the sealing line. Once subjected to strong vibration or impact, it is very likely to cause broken bags and large areas of rotten bags, which cannot effectively protect the food inside.

5. Tensile strength and inter-layer peel strength

If the inter-layer peel strength of the packaging bag is low, the tensile strength is insufficient, and the mechanical properties of the packaging bag are poor, it is easy to cause the packaging bag to be layered, and the expected load-bearing effect cannot be achieved, resulting in a decrease in the protection performance of the packaging bag and greatly shortening the shelf life of the food inside.

6. Puncture resistance

Frozen foods are generally hard after freezing, especially fish and meat products, which contain bones and hard objects. During transportation and storage, the product is easily crushed and the packaging bag is easily punctured, resulting in damage to the sealing of the packaging bag. Therefore, frozen food has high requirements for the puncture resistance of packaging bags.

7. Compression resistance

During transportation and handling, transportation packaging, even internal sales packaging, may be dangerous due to vibration, drop or impact. Therefore, frozen food packaging should be subjected to relevant vibration or drop tests. Finally, choose the packaging materials that can protect the quality of frozen food, reflect its commercial value, and make the overall packaging cost reasonable.