At present China's plastic film market prospects are very broad. The synthetic resins used in the production of plastic film mainly include polypropylene, polyvinyl chloride, polyethylene and polyester. Processing mode for blow molding, bidirectional extension, such as flow delay. In developed countries, coextruded film accounts for about 40% of all soft plastic film, while in China it only accounts for about 6%. The development of co-extrusion packaging film will also change the product structure of multi-functional film, which is applicable to beverage, milk, fresh meat and other food packaging. PET is one of the largest food rigid package resin dosage, and its market demand growth is higher than the food plastic rigid package overall growth, our country is the world's first big fruit and vegetable production and sales of power, however, about 30% of fruit during storage, transportation, sales loss, which due to improper packing is one of the reasons for the loss of fruit rot. Packing plays an increasingly important role in the competitive market. Although the physical properties of different fruits are different, water loss, discoloration, flavour and decay are common problems. Therefore, in-depth research on inhibiting metabolic processes, reducing the consumption of nutrients and maintaining the flavor quality of fruit is an important topic for fresh packaging. At present, polyethylene film and polypropylene film are the most widely used packaging materials for fresh fruits and vegetables.
Plastic flexible packaging food safety problems in the process of manufacture in order to increase its viscosity, transparency and flexibility, increased the amount of plasticizer in PVC cling film, and plasticizer contain a kind of compound medicament, it is of great damage to human body endocrine system, would disrupt the body's hormone metabolism, also easy to penetrate into food, especially fatty foods, and just the cooked food in the supermarket are mostly high fat food. Over a long period of time, the fat in the food can easily dissolve the harmful substances in the plastic film, and upon heating, the chemical compound in the plasticizer can be released into the food. After edible, can cause a woman to contract breast cancer, birth defect of the newborn, male sperm number is reduced, even mental disease. The main component of plastic stabilizer is lead stearate, which is also toxic. The salt is easy to release, and once in the body can lead poisoning. These toxic substances are eaten with food and are harmful to human health. Especially with polyvinyl chloride (PVC) plastic bags, the holding temperature 50 ℃ to 60 ℃ food, lead will dissolve into the food bag.
The expert reminds specially, when packing the food that eat directly with plastic bag such as cooked food, snack, had better not use the plastic bag that has color. Because the pigment used for dyeing plastic bags is highly permeable and volatile, it is easier to seep out when oil and heat are encountered. Organic dyes can also contain aromatic hydrocarbons, which can have health effects. At present, some brands of plastic baby bottles are sold in the market, and their color patterns contain heavy metals that are harmful to health.
Consumers can't distinguish between food and non-food plastic bags, so a considerable number of unqualified plastic bags are used in food packaging, seriously endangering people's health. The substandard plastic bags currently in use on the market are mainly recycled plastic products and even made from recycled waste plastics.
Most of these plastic packaging bags come from some small individual plastic bag processing plants, low production cost, simple process. Packaging foods in such plastic bags, especially those packaged in bulk and imported directly, does not meet food hygiene standards and can harm the health of consumers. These plastic packaging are full of bacteria and even viruses, and substandard food packaging can contaminate food and affect health. In particular, some food packaging bags when the heat or packed into more hot food, will decompose some toxic substances, will affect human health. As early as the 1990s, the ministry of health of the People's Republic of China (moh) stipulated that "recycled plastics shall not be used in the processing of plastic food utensils, containers and food packaging materials. And medical devices are not allowed to use recycled plastic.
While most plastic food bags are safe to use, there are ways to use them. Don't keep hot food in plastic bags for long. In daily life, people often see some steaming Fried cakes, Fried bread sticks and so on in plastic bags. If they are eaten for a short time, there is no great harm. However, if the overheated food is kept in the bags for a long time, some substances in plastic will leak out and affect the health. Heat food in the microwave, preferably in a plastic bag and container. Use plastic wrap instead of plastic bags. The special material of plastic wrap has good air permeability and fresh-keeping performance. If the ordinary plastic bag is used for a little longer, the food will deteriorate and rot, which cannot reach the purpose of fresh-keeping.s