Its molecular structure is so strong that it can hardly be degraded. After entering the human body, it may continue to the next generation with blood or body fluids. In other words, the kitchen helper we are pursuing does not stick to the pot, which may be "harmful to the pot" because it contains PFOA. What is the truth of the matter? Is non-stick pan really toxic and carcinogenic? Does the peeling of the coating mean that these toxic ingredients have entered the human body with food? Can it still be used after removing the coating?
Where does the saying that non-stick pan is toxic and carcinogenic come from?
During the Manhattan Project, 3M Company of the United States developed a chemical for making tank waterproof coatings, one end of which is a long-chain fluorocarbon group, and the other end is a hydrophilic hydroxyl group, which has a very strong molecular structure.
As a new substance, the toxicity and pollution of PFOA are unknown for the time being, and the cost is extremely low. However, with the Teflon non-stick pan produced by DuPont being popular all over the world, scientists have discovered the carcinogenicity and toxicity of PFOA, and the remarks that non-stick pan is toxic and carcinogenic are also rampant.
Dr. Roy Planck accidentally discovered tetrafluoroethylene in the experiment, and then DuPont registered the trademark "Teflon" and produced Teflon, a polymer made of tetrafluoroethylene. A French engineer accidentally discovered that PTFE can prevent the fishing line from knotting, and he related it to the scene of sticking to the pot when frying fish. He speculated that PTFE could also avoid sticking to the pot, so he tried to produce it.
Non-stick pans with Teflon as the main component quickly swept the world as soon as they were sold, and were deeply loved by housewives all over the world. However, a test report broke the joy. The supplier released the toxicity report of PTFE, and the conclusion showed that PTFE caused abnormal embryonic development in mice! The phenomenon of fetal malformation and cancer of DuPont assembly line workers further proves this fact. Subsequently, after a farmer used Teflon products, more than 200 cows died unexpectedly. In the investigation, it was found that PFOA caused harm to human body.
PFOA is a persistent organic pollutant, which can exist in the environment for a long time and has a long half-life. PFOA can affect human health and harm the environment through food chain accumulation. Its Chinese name is perfluorooctanoic acid, which is mainly used as a dispersant for polymers such as polytetrafluoroethylene. It has a strong physiological toxicity, which is related to six kinds of cancers and is persistent.
In fact, DuPont has already discovered the toxicity of PFOA, but in order to reduce the cost, it still uses PFOA as an aqueous solution to manufacture Teflon, which failed to bear the corresponding corporate social responsibility and despised people's life and health, so it was sued. The words such as deformity, cancer and death are shocking. Teflon has also been labeled as "polymer" and "plastic king", and the non-stick pan with Teflon as the main component is toxic and carcinogenic.
Can the use of non-stick pan cause cancer?
People think that Teflon is toxic and non-stick pan causes cancer. Is that really the case? In this regard, CCTV Life Tips and beijing university of chemical technology made relevant experiments together. The researchers scraped a part of Teflon coating from the non-stick pan and weighed it in a small container. Subsequently, experts used a thermogravimetric analyzer to detect the decomposition temperature of the coating. After an hour's observation, they concluded that the decomposition temperature of Teflon was about 300℃. In short, Teflon only begins to decompose at 300℃.
Professor Xiong Jinping from beijing university of chemical technology said: PTFE will not begin to decompose until it reaches the decomposition temperature. At different temperatures, the decomposition products and toxicity are different. To further verify, the researchers also poured cooking oil to test the temperature in the non-stick pan when heating.
The results show that:
When the oil in the pot reaches a state suitable for cooking, the temperature in the pot is about130℃; When the oil starts to smoke, the temperature in the pot is about 200℃; When the smoke began to choke, the temperature in the pot was 300℃. But under normal circumstances, when the oil starts to smoke, we start cooking. At this time, the temperature in the pot is only 200℃, which does not meet the temperature conditions of Teflon decomposition.
Therefore, generally speaking, the non-stick pan can be used normally when the temperature in the pan does not exceed 300℃ under the condition of avoiding high paste and high oil smoke. In fact, Teflon itself is non-toxic and has high stability. It is not only cold and heat resistant, but also acid and alkali resistant.
At present, the main component of the common non-stick pan coating on the market is still polytetrafluoroethylene, in which polytetrafluoroethylene (PTFE) needs to be polymerized by solvent, then coated on the surface of the pan, filled with uneven places, and baked to form a smooth film.
If you look closely, you will find that the inner surface of non-stick pan is very different from ordinary iron pan and steel pan. PFOA has been banned in many countries, but in this process, some unscrupulous merchants will illegally use perfluorooctanoic acid for processing, just like DuPont. Without volatilization, high-temperature cooking still poses a cancer risk.
Therefore, when buying non-stick pans, we should choose formal channels and choose non-stick pans that meet national standards to fundamentally avoid risks. It should be noted that the temperature of Teflon non-stick pan can reach 800℃ after drying for 5 minutes, and the toxic gas perfluoroisobutylene is decomposed, which is harmful to human health. Therefore, the non-stick pan should avoid long-term dry burning.
Can the coating of the non-stick pan be used if it falls off?
If the non-stick pan is used for a long time, or it is often bumped, the coating will scratch and fall off. Some people worry that these dropped paints will do harm to human body if eaten, and I wonder if they can continue to be used.
In this regard, experts said: PTFE is very stable. For a regular non-stick pan, even if it is eaten by mistake after falling off, it will not decompose in the human body and will be excreted with metabolism.
Once the coating of the non-stick pan falls off, it no longer has the characteristics of "non-stick", and it is easy to burn or stick in the process of cooking and frying food, which will produce more harmful substances, increase the risk of cancer and make it more difficult to clean. Therefore, when the coating of the non-stick pan falls off, it is best to replace it with a new pan to avoid unnecessary trouble.