How to use plastic products safely?

Plastic packaging materials have a wide range of applications in the field of food packaging. Plastic flexible packaging materials are relatively inexpensive and have a special role in the production of modern foods, especially liquid foods. Even the inner layer of the can is coated with a plastic component such as epoxy resin or styrene. At present, many paper packaging materials used for food are often composite papers of polyethylene coating film. Without plastic packaging materials, the packaging cost of many foods will increase significantly. For example, liquid milk, beverages and many other types of food can only be used in glass containers.

There are many hidden dangers of plastic materials used in food packaging, such as residual solvents, stabilizers, plasticizers, antioxidants, colorants and preservatives in materials, as well as unpolymerized free monomers and their plastic products. The toxic components or toxic elements of organic substances such as residuals of degradation products may migrate into food. In the absence of strict regulatory measures, the abuse of plastic materials on food products can seriously damage consumers' health. There are many types of plastic products for food packaging, such as films, bags, bottles, boxes, trays, etc.

1. Chemical types of plastic films and bags

In terms of food packaging, plastic film is the most widely used. Plastic bottles are also used in many bottles, cans, and boxes of food packaging. Plastic film and plastic bag materials are classified into polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), and polyvinylidene chloride (PVDC).

PE is the most widely used in daily life and has stable chemical properties. It is usually made into membranes, bags and various containers, and is resistant to acids, alkalis and salts. Relatively speaking, pure PE plastics have low heat resistance and are easily softened and deformed when exposed to heat (such as boiling water). But now PE products are generally improved with additives, and some can withstand the high temperature of 100C.

PP is non-toxic, tasteless, and can be immersed in boiling water at 100 °C without deformation, damage, acid and alkali resistance.

Bags and membrane materials that are in direct contact with food are generally PE, PP, PVDC, and the like.

Plastic film and bag for kitchen are generally PE or PP.

Many edible paper packaging devices are also often coated with PE or PP, such as disposable paper cups, dishes, bowls, boxes, and the like.

Because PVDC has good properties of moisture barrier, oxygen barrier, moisture resistance, acid and alkali resistance, oil immersion resistance and resistance to various chemical solvents, it is often used in the packaging of casing films such as ham, bacon and other foods.

The inner layer of the composite plastic film packaging material (the surface layer in contact with the food) is generally a PE or PP material, and the two materials are less harmful. The outer layer of the composite plastic film or the material of the outer packaging of the food product is usually PVC.

Second, how to safely use plastic film products

It is not advisable to use plastic bags to hold liquid foods with high temperature and high oiliness.

It is common to have people in food stalls, using plastic bags to hold hot tofu brains, hot soy milk, etc. Some vendors sell the fritters and oil cakes that have just been out of the pot in plastic bags for the purchaser to carry. There are still many early stalls, which put plastic film bags on the dishes and hold hot food. Food suppliers are willing to do this because it saves the hassle of cleaning dishes. Many consumers also think that this is more hygienic and will not transmit germs through dishes. However, many plastic film bags that are eaten by food stalls are inexpensive and inferior products produced by informal manufacturers. Such plastic films may contain more harmful components. Even plastic film bags produced by regular manufacturers contain trace amounts of harmful components, and long-term liquid and high-temperature foods promote the dissolution of such harmful components. Therefore, in daily life, it is necessary to avoid using plastic film bags to store hot and hot food for a long time.

Avoid boiling water to heat food in plastic packaging. Although some manufacturers indicate on the packaging, some soft-packed foods (such as fish, canned meat, eggs, corn, etc.) can be cooked together with the package. However, it is safer to remove the packaging and heat the food directly in the pot or in a porcelain or glass container. Even if there is no condition to remove the packaged food, the packaged food cannot be heated directly in the pan, but should be steamed and heated. Because the temperature of the package directly in contact with the pot will be very high, even exceeding 100C, making the plastic more easily decomposed and releasing more harmful components.

Do not heat ordinary plastic bags (non-cooked bags) such as milk, beverages, etc. directly. Even in plastic bags that can be used for high-temperature heating, including some composite plastic bags, the additives, binders, and dyes contained in the raw materials are more likely to overflow at high temperatures.