Share this! Don’t use the plastic bags in supermarkets like this anymore!

Expert of this article: Yang Chao, PhD in Chemistry, University of Chinese Academy of Sciences

If you like shopping in supermarkets, you can’t live without it - roll-up bag.

Generally, the fresh food section of large supermarkets will have several rolls of bags, which are used to hold everything from fruits and vegetables to chicken, fish, eggs and meat.

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The setting of roll bags makes it convenient for customers to take the goods by themselves, but they are usually tied with a rope to prevent some people from "pulling" them endlessly.

What is the difference between the roll bags in supermarkets and other common food plastic bags?

Can the purchased food be stored in the plastic bag in the refrigerator or heated in the microwave?

Which plastic products cannot be reused?

You will know everything after reading this article!

What are the roll bags in supermarkets made of?

To understand the materials of plastic roll bags in supermarkets, we must first understand what categories of plastics are divided into.

Common plastic products can be generally divided into seven categories: polyethylene terephthalate (PET/01), high-density polyethylene (HDPE/02), polyvinyl chloride (PVC/03), low-density polyethylene (LDPE/04), polypropylene (PP/05), polystyrene (PS/06), and other plastics (PC/07). All of them have a triangular recycling mark.

The inside of the triangle is marked with serial numbers 01 to 07, among which No. 1 PET, No. 2 HDPE, No. 4 LDPE, No. 5 PP, and No. 6 PS can be used to hold or contact food.

Food plastic bags are generally made of No. 2 HDPE, while food cling film is generally made of No. 4 LDPE. These two materials are the most common plastics in the food area of ​​supermarkets.

It takes hundreds of years for roll bags made of "pure PE plastic" to degrade. In order to prevent white pollution and control the use of roll bags, supermarkets usually tie a rope on the roll bags to prevent people from pulling off multiple roll bags endlessly.

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Of course, some supermarkets will choose degradable roll bags, which can be divided into two categories: bio-based and petroleum-based. They refer to adding some special ingredients to plastic to make it easier to degrade. Degradable plastic bags can generally be decomposed within a year, and Olympic environmentally friendly plastic bags can even begin to decompose within less than three months after being discarded.

Degradable plastic bags have the following characteristics:

In line with the national standard GB/T21661-2008, it is marked with the abbreviations of polymer materials such as PLA, PHAs, PBA, PBS, etc. The most common one is the plastic bag with the number "53" in the triangular recycling mark. If it is a plastic bag for food, it will also be printed with the food safety license QS mark.

In addition, not all plastic bags or plastic wrap marked with PE/HDPE/LDPE can be used to wrap food. You must pay attention to the words "food only", "food safety license" or "QS" before they can be used to hold food.

Common plastic bags for garbage are also made of PE. Never use them to hold food! Generally speaking, plastic bags that cannot hold food often have excessive plasticizers and contain harmful substances such as phthalates.

Will food fat dissolve plastic bags?

Some people found that the plastic bags of takeaway fried skewers were soaked with oil and wondered if the fat in the food dissolved the plastic bags?

In fact, it is not the case. Plastic bags are polymer materials, which are made of ethylene molecules. There are gaps between polymers, and the "oil molecules" in food can pass through them, causing oil seepage. High-density polyethylene plastic bags have small molecular gaps, so it is not easy to seep oil. Low-density polyethylene molecular gaps are relatively large, so it is easy to seep oil. This is also the reason why you will get oily hands even if you wear gloves when eating crayfish.

Is eating fried skewers in plastic bags harmful to the body? If the temperature is not taken into account, the oil will only seep out of the plastic bag and will not dissolve the plastic bag, so there is no need to worry about eating the "liquid plastic bag".

Can plastic bags be stored in the refrigerator together with food?

Many people are used to storing vegetables, fruits or meat bought from supermarkets directly in the refrigerator. It is fine to put them in the refrigerator, but if you put a piece of freshly bought minced meat in the freezer, the plastic bag or plastic film and the minced meat will stick together tightly. When thawing, the plastic bag will most likely be torn into pieces first, and tiny pieces of the plastic bag will remain in the minced meat, which will cause microplastics to be ingested when eaten, causing harm to the human body.

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Therefore, when eating frozen food, be sure to wait until the food thaws and can be easily separated from the plastic bag before taking it out of the plastic bag.

What about heating it in the microwave together with food?

Not only low temperatures, but also using plastic bags in high temperature environments will have an impact.

Studies have shown that using plastic food bags to pack high-temperature soup foods can cause the phthalate plasticizers (PAEs) contained in the plastic food bags, such as dibutyl phthalate, diisobutyl phthalate, and di(2-ethylhexyl) phthalate, to be released into the food. Moreover, as the packaging time increases, the content of phthalates will increase. The intake of phthalates will have the risk of causing cancer, teratogenesis, mutagenesis, and damage to the reproductive system.

It is recommended that everyone should reduce the use of plastic bags to pack food with higher temperatures.

Similarly, when heating food with a plastic bag, not only will the plasticizer phthalate in the plastic bag be released faster, but it will also dissolve into the various fats in the food, allowing you to "absorb" the plasticizer more effectively! Therefore, everyone should never heat food with a plastic bag.

Which plastic products cannot be reused?

Do not use food-specific plastic bags to repeatedly hold food! Although food-grade plastic bags will not be affected by plasticizers at room temperature, repeatedly using a plastic bag to hold different foods will lead to the growth of bacteria and mold, causing the food to spoil faster, thus affecting your health.

For disposable plastic lunch boxes, before you plan to use them multiple times, you must check whether the label on the bottom of the box indicates that it is made of PP (05). If it is made of PP, it can be used for a long time and multiple times without any problems, even if you heat it in a microwave. This is because PP is polypropylene, which can withstand temperatures of 130°C and has a melting point of up to 167°C.

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At the same time, you should also pay attention to the material of the lunch box lids. Most of the lids are made of PE, so don't put PE plastic lids in the microwave to heat. In addition to PP lunch boxes, you will also encounter disposable lunch boxes made of PE and PS in your life. Harmful substances will be released after heating. These two types of disposable lunch boxes should not be reused.

Do not use disposable plastic spoons, cups, and straws multiple times in your life. Although the possibility of being affected by plasticizers is small, the risk of ingesting microplastics is high.

In short, everyone must remember this: do not let plastic products with the "disposable" label come into contact with food repeatedly!

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