Plastic lunch boxes microwave heating or release harmful substances
news on August 17: it is reported that in response to the problem that plastic packaging boxes for lunch boxes in some convenience stores may not be suitable for microwave heating, many convenience stores such as the whole family, Rosen, 7-Eleven and so on yesterday responded that either the lunch boxes have been removed from the shelves without identification, or the materials have been inspected and confirmed to be safe, and suppliers will be required to mark clear plastic codes on the lunch boxes in the future
whether there is a code at the bottom of the box is very random
the day before yesterday, I learned about the heating of plastic lunch boxes in many convenience stores
● family convenience store on Henan South Road: the number in the triangle area at the bottom of the "Orleans chicken leg rice" box is 5, which belongs to a kind of plastic that can be heated by microwave. After the lunch box was heated in the microwave oven for one minute, the plastic box hardly changed
● 7-Eleven convenience store on Henan South Road: there is no sign on the package of "table style stewed rice". After heating in the microwave oven for 1 minute and 30 seconds, the plastic wrap covered on the lunch box has melted and deformed, and the lunch box that originally bulged out has also sunk. With a touch of your hand, the lid of the lunch box softened a lot
● the logo on the bottom of the white packaging box of "Sichuan style chicken nugget rice" in the Xishi convenience store on Hankou Road is 7, indicating that "it can be heated in a microwave oven"
● Haode convenience store on Shanxi South Road: there is also a plastic lunch box marked with 7, which is marked "it can be heated in a microwave oven"
● Rosen convenience store on Shanxi South Road: there is no number on the bottom of the "rice covered with beef in tomato sauce" box, so we can't know the specific type of packaging box
the clerk was required to "open the lid and heat up", and the supplier was required to print the code.
GU Xing, director of Shanghai family convenience goods department, said yesterday that since the relevant parties had no mandatory unified regulations on the packaging and recycling identification of plastic lunch boxes, the plastic lunch boxes in the convenience store were indeed marked with 5, 7 and no code. In these packaging boxes, polypropylene (PP) is still the main material with code 7 or no code, which meets the conditions of microwave. Of course, some materials may be heated by microwave, but they may not be the most suitable. In order to avoid the situation that it is difficult for consumers to distinguish, the whole family convenience has removed all plastic lunch boxes from the shelves except for code 3, the sliding surface of the inlaid steel plate in contact with the lining plate, and the dovetail groove surface on the lining plate should be kept clean. 5 this practice will continue in the future
Li Jiahao of the public relations department of uni president supermarket (Shanghai) convenience Co., Ltd. said that at present, the company has tested all the plastic packaging boxes that need to be heated, such as lunch boxes, noodles, triangle rice balls, etc. in the 7-Eleven store. The test results obtained yesterday showed that the materials of these plastic lunch boxes are polypropylene, which is safe. Li Yongwu analyzed the current situation of China's plastic industry. The company is negotiating with the suppliers of plastic lunch boxes and requires them to mark clear plastic codes on the lunch boxes in the future. Li Jiahao said that since the lid of the plastic lunch box is usually different from the material of the lunch box itself, in the future, each store of 7-ELEVEN will also put forward corresponding tips to greatly improve the management and utilization efficiency. Clerks are required to open the lid of the lunch box when heating food in the microwave oven. After communicating with the supplier, the plastic lunch box in the convenience store will also be pasted with the prompt of "it is recommended to open the lid and heat up" in the future
last night, an official from Shanghai Hualian Rosen Co., Ltd. said that the plastic lunch boxes in Rosen's store, regardless of the code, are all tested safety packaging. The reason why some lunch boxes are marked with code 5 and other lunch boxes are not marked with relevant marks is mainly because there was no unified mandatory standard before, and some lunch boxes of manufacturers were not printed with code on their molds. In the future, Rosen will require the lunch box supplier to unify the plastic code identification as soon as possible
the number at the bottom of the plastic packaging box represents different meanings
"1" -pet (polyethylene terephthalate): it will produce carcinogens after 10 months of use. It can be used only with conventional accessories
this kind of plastic has a high probability of being discarded after use, and is usually used to make mineral water bottles, fruit juice bottles, etc
"2" -hdpe (high density polyethylene): not easy to clean, easy to breed bacteria. Usually, the packaging bottles of shower gel and shampoo we use belong to this material
"3" -pvc (polyvinyl chloride): it is easy to produce carcinogens in case of high temperature and grease. It is usually used to make fresh-keeping film, plastic toys, plastic containers, etc
"4" -ldpe (low density polyethylene): it is easy to produce harmful substances under high temperature. Plastic bags and various film products commonly used in daily life will use this material
"5" -pp (polypropylene): special material for microwave oven lunch box
"6" -ps (polystyrene): heat resistant and cold resistant, cannot be used in microwave. Plastic cups and fragile plastic cake boxes generally belong to this kind
"7" -ab (acrylonitrile butadiene): cannot be used in food packaging. But before 2008, code 7 mainly refers to all plastics except 1-6. Plastic milk bottles and plastic buckets for drinking fountains are usually marked with "7"
polypropylene with code 5 can be heated in a microwave oven for a short time
"at present, the plastic type recognized by the industry that can be heated in a microwave oven is polypropylene, that is, the plastic type with identification code 5." Dong Jinshi, executive vice president and Secretary General of the International Food Packaging Association, said that polypropylene material can withstand 130 ℃ high temperature, so it can be heated in a microwave oven for a short time. In addition to polypropylene plastic with code 5, the most common codes are 1, 2, 3, 4, 6 and 7, but the plastic types of these codes are not very high-temperature resistant, and polystyrene plastic with code 6 can only withstand temperatures below 100 ℃
code 7 has two new and old standards
for the case of code 7 at the bottom of lunch boxes seen in many convenience stores, Dong Jinshi said that according to the standards before 2008, plastic with code 7 is all kinds of plastic except 1-6 (collectively referred to as "others"), some of which can be used for food packaging and heating
after the official implementation of the standard gb/t of plastic products in 2008, code 7 specifically refers to acrylonitrile butadiene (AB), which is not allowed to be used as food packaging. However, since the standard is not a mandatory standard, after the implementation of the new standard in 2008, the identification of plastic types with code 7 has not been completely unified. Therefore, until now, there are still a large number of old plastic lunch boxes with the logo of 7 (oth-ers) in the market, which makes it difficult for consumers to identify
it is best to remove the cling film when heating
during the interview, it was found that the clerks in many convenience stores usually do not remove the cling film wrapped outside the packaging box when heating the lunch box. In this regard, experts warned that the PVC film may melt after heating for a long time, and the plasticizer (i.e. plasticizer) released under high temperature will be transferred to food, causing harm to human body. Therefore, even if the packaging box is made of polypropylene material with code 5, it is best to remove the fresh-keeping film outside when heating
in addition, in daily life, you should also try to avoid letting the fresh-keeping film contact with foods containing a large amount of oil, such as fried eggplant, boiled fish, etc., because the oil temperature can exceed 200 ℃ at the highest, and the hot oil is very easy to cause the molten fresh-keeping film to release harmful substances
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