Can Plastic Products Be Heated in a Microwave?
author: Iris
2024-08-30
Plastic is everywhere in our lives. The buns and fried dough sticks we buy in the morning, and the takeaways we order at noon and in the evening are all packed in plastic bags and plastic boxes. Can plastic products be heated in a microwave? Will hot food in plastic produce harmful substances? What is the truth? Let's follow YANGRUI to find out today!
1. Can Plastic Bags and Plastic Boxes Be Heated?
There is a triangle composed of three arrows on plastic products, representing a cycle. The middle number represents different materials, mainly polyethylene (PE), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), etc.
Number 1: Polyethylene (PE)
Polyethylene (PE) is the most common plastic bag material. Because it is non-toxic, tasteless and odorless, it can be used for packaging ordinary fruits and vegetables. The melting point of polyethylene is 100-130℃, and it cannot be heated in a microwave or steamed in a pot.
Number 2: High-density polyethylene (HDPE)
HDPE is often used in medicine bottles and boxes of daily necessities, such as shower gel and shampoo, which generally do not need to be heated.
Number 3: Polyvinyl chloride (PVC)
PVC is used as toys, containers, etc. It is afraid of heat and oil, and usually does not hold food, let alone heat.
Number 4: Low-density polyethylene (LDPE)
Low-density polyethylene has poor heat resistance and cannot be heated. It is generally only used for fresh-keeping bags, plastic boxes, etc.
Number 5: Polypropylene (PP)
Polypropylene (PP) is the only plastic product that can be used for heating. The operating temperature range is -30 to 140°C. It can be heated in a microwave oven and refrigerated in a freezer.
Number 6: Polystyrene (PS)
Polystyrene is less stable than polypropylene and is often used as foam padding or disposable packaging boxes.
In other words, the plastic bags that we commonly use to hold buns, steamed buns and other foods cannot be directly heated in a microwave oven. It is best to heat it in a microwaveable ceramic bowl like Zeng Quan did. As for takeout boxes, you should judge whether the material is suitable for heating based on the label on the outer packaging.
Number 7: Other categories (OTHER)
OTHER is collectively referred to as PC other categories, which is polycarbonate. The most used one is polycarbonate, which can be used to make baby bottles and kettles. It is best not to use it to hold hot water above 70 degrees Celsius.
Experts say that disposable lunch boxes made of polypropylene (PP) can be heated at a maximum temperature of no more than 120° and can be placed in a microwave or steamer. However, polystyrene (PS) lunch boxes, that is, disposable polystyrene foam lunch boxes, can only be heated to 90°. After exceeding 90°, styrene will be released into the food, which may harm the liver and kidney function and central nervous system of the human body. If used for a long time, there is a risk of cancer.
2. Are All the Plastic Lunch Boxes You Bought Qualified?
Regarding how to choose plastic lunch boxes, YANGRUI summarizes four points:
2.1 Look at the packaging
The most important thing is to see whether the appearance of the plastic bag is printed with food-specific text labels such as "food grade" and "for food" or knife and fork patterns. PP5 materials should be selected for microwave heating.
2.2 Touch the appearance
A qualified lunch box should have a smooth surface and uniform color. Everyone should try to choose products without decorative patterns.
2.3 Smell the smell
A normal lunch box should be odorless and tasteless. You can smell it after purchase to see if there is any peculiar smell. Using a smelly lunch box to hold food may cause food safety problems, so you should avoid buying and using it.
2.4 When using plastic lunch boxes, you should also pay attention to the following points:
① Remove the lunch box lid when heating.
It should be noted that some microwave lunch boxes are made of PP5, but the lid is made of PE4, and PE cannot withstand high temperatures. Therefore, YANGRUI recommends that you remove the lid when using plastic lunch boxes for heating.
② Replace in time
The service life of lunch boxes is generally 3-5 years, but when they change color, become brittle, or turn yellow, they should be replaced immediately.
③ Clean thoroughly
Some lunch boxes will be equipped with sealing rings on the lids to ensure sealing. But when food residues penetrate into the sealing rings, it becomes a "blessed land" for mold.
YANGRUI recommends that you clean the sealing rings and their grooves every time you wash them, dry them, and then put them back on the lid. Of course, if you think it's too troublesome, you can also buy microwave-safe glass bowls or lunch boxes made of other materials.
3. Can PP5 Plastic Boxes Be Reused?
Nowadays, many takeout boxes not only look good, but also have a relatively safe PP5 material at the bottom. Some frugal people reuse them.
In theory, PP5 can be reused. But if it is used many times and the external conditions change, such as high temperature or contact with grease, it will destroy its stability and cause harmful substances in it to precipitate, which may affect health in the long run. Therefore, YANGRUI recommends that you try to reduce the frequency of repeated use, avoid direct contact with boiling water during use, and do not add seasonings, oil products, etc.
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