Is the lunch box poisonous to heat? Disposable tableware is the product of fast-paced life, and there is no need to use tableware that has been used back and forth. At present, disposable snack boxes on the market are all made of polystyrene raw materials extracted from petroleum and foaming agents. Are the following shared lunch boxes poisonous for heating?
Is the lunch box poisonous? 1 Is it toxic to heat disposable lunch boxes?
The epidemic has slowed down recently, but people's awareness of prevention is still very strong. Some netizens are worried that the takeaway package will be infected with the virus, so they put food and disposable lunch boxes in the microwave oven to heat them.
Heating disposable lunch boxes is toxic, and long-term consumption of food in disposable lunch boxes may cause cancer.
Is it really toxic to heat disposable lunch boxes?
In this regard, China Food Safety Network reporter interviewed Yi Zhu, an associate professor at the College of Food Science and Nutritional Engineering of China Agricultural University.
"Whether a disposable lunch box is toxic or not depends on the material." Yi Zhu, an associate professor, said, "There are basically two kinds of disposable lunch boxes on the market, polypropylene (PP) and polystyrene (PS)."
Disposable lunch box made of polypropylene (PP) can be heated up to 120, and can be put into microwave oven or steamer.
But the polystyrene (PS) lunch box, that is, the disposable polystyrene foamed lunch box, can only be heated to 90℃. When the temperature exceeds 90℃, styrene will be released into food, which is harmful to liver and kidney function and central nervous system. If used for a long time, there is even a risk of cancer.
Some merchants will also use polypropylene material through the box body and polypropylene material for the box cover to balance the cost. This is why people sometimes see that the lid of the disposable lunch box has melted and deformed after it is taken out of the microwave oven, and even some small holes appear.
If you encounter a disposable lunch box made of this kind of "splicing material", it is better to take off the lid of the box, or it is safer to heat it with the lid of your used lunch box.
Transparent polypropylene lunch box
Polystyrene foam lunch boxes
Toxic migration of disposable lunch boxes
Faced with the view that some disposable lunch boxes made of materials may be toxic after heating, someone may ask.
Then I ordered takeout. Can't I eat anything in a disposable lunch box?
After the food is cooked, it also has a certain temperature. Is it poisonous to send it all the way?
Ms. Ma feedback, sometimes after take-away, you will see that the disposable lunch box has become soft and deformed, which makes people feel very uncomfortable, and it is very uncomfortable to eat and waste.
In fact, the plastic lunch box has softened, indicating that some harmful low-molecular substances in the material have begun to melt into the soup. Try to choose dinner, and soup is not recommended.
Associate Professor Yi Zhu has done experiments on this problem. Plasticizers can only be detected after one or two hours, and the migration time of monomers in other plastics is not necessarily.
In short, it is safest to finish eating as soon as possible.
Even so, it doesn't mean that you don't have to consider the toxicity of disposable lunch boxes when eating takeout.
Usually, when some netizens order food online, they will see that most merchants will charge extra packaging fees. The price of disposable lunch boxes ranges from one yuan to three yuan. I feel that the material is ok when I get it, and I will use it repeatedly.
Some netizens ordered takeout and couldn't eat. Put the remaining half in the refrigerator and heat it the next day.
Neither of these practices is desirable.
There are many kinds of additives for disposable lunch boxes, and it is impossible for us to determine the formula of each one. Even if it is the same model product of the same enterprise, many factors will prompt it to adjust the formula, so it is obviously unrealistic to judge the characteristics of additives in the box cover, and the best way is to avoid them as much as possible.
When you get the food in the disposable lunch box, the safest way is to transfer it in time, remove it from the disposable lunch box, and heat it in a heat-resistant and high-temperature-resistant lunch box for your own use.
Eat it as soon as possible. Don't leave the rice in the disposable lunch box until it is heated the next day. If the disposable lunch box is heated repeatedly, the risk will increase.
How to distinguish a safe disposable lunch box?
Disposable lunch boxes are made of different materials and have different characteristics. How to distinguish safer disposable lunch boxes?
Look at the hardness and smell.
You can smell it, if there is obvious pungent smell, don't choose; You can pinch it. Inferior disposable lunch boxes are easy to tear and not hard enough. Holding food may even burn the lunch box.
Avoid low prices and no products.
Try to choose a disposable lunch box made of polypropylene with a slightly higher price. The stability of polystyrene is not as good as that of polyethylene, so it is more dangerous.
You can see if there are relevant certificates, and don't choose some unknown three-no products.
Look at the appearance
Don't choose a disposable lunch box with bright colors and too dark, which may cover up the original color of the lunch box.
And pay attention to whether there are impurities and mildew on the surface of the lunch box, which may be "refurbished" products made of waste plastic.
Look at the safety sign
Have you found some transparent protrusions on the disposable lunch box, which are safety signs, with a grade of 1234567?
At present, the main packing boxes on the market are 1, 5 and 6, which are generally safe.
1 No.6: The heat resistance is poor, so it can't be heated and can't hold high-temperature food. The plastic bottles of mineral water, fruit juice and carbonated drinks are made of1; Now many milk tea cups are covered with number 6;
No.5: It can withstand the high temperature of about 200℃ and can be heated by microwave oven. Repeated heating will not be a problem.
Therefore, only the plastic made of No.5 pp can be put into the microwave oven for heating.
Although resistant to high temperature, some components in plastic products are fat-soluble. If the oil content in food is high, it is very beneficial to their dissolution. Although it is not necessarily harmful, it is not a good thing. Can be avoided as much as possible.
For example, maocai, boiled fish, Maoxuewang ... Don't pack these greasy foods on the premise of controlling your appetite.
Is the lunch box poisonous? 2. Can disposable lunch boxes be heated by microwave?
It can be said that anything with a non-conductive shell can be used as a disposable lunch box. Generally speaking, as long as there are no metal utensils, such as disposable lunch boxes, foamed plastics, paper products and instant noodle bowls, they can be heated.
Pay attention to heating matters
First, food can't burn glue. Like bones, be careful not to heat them for too long. The bones are burnt, and so is your lunch box.
Second, the disposable lunch box can be heated by microwave oven, but it is best not to heat it in this way. If the disposable lunch box is heated by microwave oven, it will release harmful substances, and frequent use will lead to physical injury.
Apparatus suitable for microwave heating
1, ceramic ware: there are heat-resistant ceramics and ordinary ceramics. Pots, plates and other utensils made of heat-resistant ceramics are suitable for long-term use in microwave ovens, while ordinary ceramic utensils can only be used for short-term heating. In particular, it should be reminded that ceramic utensils containing gold and silver wires will generate sparks when used in microwave ovens, so they are not suitable for use.
2. Plastic utensils: various utensils made of polypropylene, polypropylene resin, composite polypropylene, polysulfone and other materials can withstand the temperature above 120 degrees Celsius and can be used for microwave heating. The container made of PET resin and polyester material can withstand the temperature above 220 degrees Celsius and can be used for barbecue. Of course, PP is the most special microwave oven among disposable lunch boxes.
3. Glassware: Glassware made of borosilicate glass, glass-ceramics and titanium oxide crystal glass is suitable for long-term use in microwave ovens because of its good microwave penetration, stable physical and chemical properties and high temperature resistance (up to 500 degrees Celsius or even 1000 degrees Celsius).
4. Metal utensils: all kinds of utensils made of metal materials such as aluminum, stainless steel and enamel. Because the microwave can't penetrate and the food inside can't be heated, it is not suitable for use in the microwave oven.
Is the lunch box poisonous? It's very hot. Toxic, because disposable lunch boxes can only hold warm food, and toxic substances will seep out at high temperature. Many materials of this disposable lunch box are not up to standard, not to mention high temperature, so for the sake of safety, never use disposable lunch boxes to heat at high temperature.
Plastics are mostly made of polyvinyl chloride, which releases toxic substances when exposed to high temperature, and it is harmful to health when it enters the body with meals.
According to the latest issue of Environmental Watch magazine in the United States, phthalate esters, a synthetic chemical widely found in plastic toys, bottles, cosmetics and other plastic consumer goods, may harm the reproductive organs of baby boys, affect the development of children's sexual characteristics, and even lead to reproductive system cancer.
Almost at the same time, a paper published in Endocrinology Monthly pointed out that phenol methane, also a chemical commonly used in plastic products, may cause breast cancer in women.
Hot soup in plastic bags can cause cancer. The main component of making plastic bags is polyvinyl chloride, and its released hydrogen chloride (HCL) is a toxic gas, especially plastic bags that have not been inspected by health departments.
The content of HCL gas released by it greatly exceeds the standard, which is very harmful to human body and easy to cause cancer. According to experts, when the temperature of food in disposable foamed plastic tableware reaches above 60 degrees, the foamed plastic lunch box will release toxic substances, which will cause certain damage to the central nervous system of human body and seriously threaten people's health.
Disposable foamed plastic lunch boxes and plastic bags for food seriously affect our health. When the temperature reaches 65℃, harmful substances in disposable foamed plastic tableware will penetrate into food, causing damage to human liver, kidney and central nervous system.
In China, almost all the ultra-thin plastic bags we use come from the reuse of waste plastics, which are produced by small enterprises or family workshops. The raw materials used in these factories are discarded plastic barrels, cans and disposable syringes.
In production, the raw materials are crushed into plastic particles by machinery, then the plastic particles are put into a pool for cleaning (called disinfection), taken out and dried, and then pressed into films by machinery to make various plastic bags. Every time we eat, many people pack their meals in plastic bags, which not only harms the environment, but also harms their own health.
The degradation time of plastic products usually takes at least 200 years. Abandoned agricultural films and plastic bags left in farmland for a long time will affect the absorption of water and nutrients by crops, inhibit the growth and development of crops, and cause crop yield reduction. If livestock eat plastic film, it will cause digestive tract diseases and even death.
Due to the soft foundation of the site after plastic film landfill, harmful substances such as bacteria and viruses in garbage can easily penetrate into the ground, pollute groundwater and endanger the surrounding environment. If waste plastics are burned directly, it will cause serious secondary pollution to the environment.
When plastics are burned, it will not only produce a lot of black smoke, but also produce dioxin, which is by far the most toxic substance. It takes at least 15 months for dioxins to decompose gradually after entering the soil, which is harmful to plants and crops.
Dioxin has serious damage to the liver and brain of animals. In addition, because disposable plastic tableware is difficult to degrade, many cities are now promoting the use of green tableware-paper tableware. The principle is that cellulose, the component of paper products, can be degraded by microorganisms. However, it is unwise to use paper tableware instead of foamed plastic tableware.
First of all, paper tableware will also bring visual pollution. Their degradation speed is not fast, and often they will not be completely degraded for dozens of days or even months.
Secondly, when making paper and tableware, in addition to straw pulp and rice pulp, wood pulp of about 1/3 should be added. If fully promoted, it will inevitably lead to the consumption of a large number of wood and the intensification of deforestation. However, the forest coverage rate in China is only 13 and 92%, and the per capita forest area is only equivalent to the world average of 17 and 2%.
Thirdly, pulping has always been a big consumer of water, energy and sewage. The pulping process needs a lot of water, and China is a country short of water. If the sewage is directly discharged into the river without treatment, it will cause water pollution;
Paper tableware needs to be dried immediately after forming, which consumes a lot of energy. China's energy structure is dominated by burning coal, which will increase the content of SO2 in the air and cause acid rain.