How to choose and use plastic wrap correctly

The preservative film mainly plays three roles:

One is to isolate and protect food from external dust, bacteria and microbes. Second, moisturize, prevent the moisture in food from volatilizing; Third, protect food nutrition from being destroyed. Not all plastic membranes can do all three. Will be appeared on the market now, he says, agricultural film and thick plastic film as a plastic wrap, but if it is too thick, can lead to food "breathing", not easy to anaerobic fermentation, thereby to rot. "Even if it's a good wrap, wrap it in one layer to keep it fresh, and wrap it in two layers to keep it fresh. The plastic wrap not only keeps the water from volatilizing, but also allows the carbon dioxide inside to go out. The oxygen outside can come in, just like a mask.

The common plastic wrap on the market is mainly divided into the following materials:

The first is polyethylene, or PE for short. The material is mainly used in food packaging.

The second is polyvinylidene chloride, referred to as "PVDC, mainly used in some cooked food, meat products, fish products such as packaging, can be used in the refrigerator, also can be used in the microwave oven, the heat resistance (140 degrees Celsius).

The third kind is polyvinyl chloride, or PVC for short. The plastic wrap of this material contains plasticizer, which is harmful to human health and is not allowed to be used in meat. At present, this kind of plastic wrap is no longer seen in regular supermarkets, but because of its low price, it will be used in some places with less strict control, such as some wholesale markets.

PVC cling film itself contains a certain amount of vinyl chloride monomer and vinyl chloride monomer or grease will dissolve into food when it is heated, although most of the PVC cling film of vinyl chloride monomer content on the market are lower than the highest standard, but the chemical is rarely out of the body, after the vinyl chloride residue in the human body excessive, human health is a serious threat.

In addition, plasticizer (plasticizer) must be added to PVC plastic wrap in the production process to make it thinner and more transparent. And cling film containing plasticizers in oil or high temperature (over 100 degrees Celsius), plasticizer is easy to be released, along with the food enters the human body, may cause the endocrine disorder, male reproductive ability, etc. Children are more vulnerable than adults.

How is the preservation function of fresh film and box?

Many people choose to keep their food in plastic containers. The crisper keeps moisture away, keeps dust away, and keeps the smell from escaping. Keep fresh film can keep moisture in general, but cannot keep taste. Fruit is preserved cooked food, the better choice is to use the fresh box.

Choose and buy plastic wrap method:

Look at the packaging. There is no "QS" mark, number and manufacturer's detailed address, PE or PE plastic wrap can be used safely. Try not to use PVC or unwritten materials.

Look at the color. The plastic wrap made of PVC has good transparency. The words on the drum can be seen on the rolled PVC film, while the words on the reel cannot be seen on the rolled polyethylene (PE) plastic wrap.

3. Rub your hands. PE plastic wrap is generally less sticky, easy to open after hand rubbing, while PVC plastic wrap is more sticky, not easy to spread after hand rubbing.

Burn it. PE plastic film burns with fire, the flame is yellow, burning quickly, leaving the source of fire will not be put out, there is dripping oil phenomenon, there is the smell of candle burning; And PVC plastic wrap is not easy to ignite, the flame root has a light green, black smoke, after leaving the fire will be extinguished, and there is a strong pungent odor.

Two types of cling film are distinguished by combustion

PE plastic film with fire, the flame is yellow, burning quickly, leaving the source of fire will not be extinguished, there is oil phenomenon

PVC plastic wrap is not easy to ignite, the flame root has a light green, black smoke, after leaving the fire will be extinguished, and there is a strong pungent odor.

Go to the supermarket. Supermarket sales are generally PE film, agricultural market sales are mostly PVC film.