Documentary The Devil We Know (Source: IMDb)
According to the documentary, the production of non-stick pan needs a raw material PFOA, also known as C8. This substance not only exists widely in the environment, but also is carcinogenic.
Screenshot of related articles (Source: weixin.qq.com)
So we have two questions: On the one hand, is PFOA really that terrible? On the other hand, if PFOA is toxic, will it appear in the non-stick pan? Even if not, are there any other safety hazards in the non-stick pan?
PFOA refers to perfluorooctanoic acid, which is a widely used industrial raw material.
At the end of last century, employees of DuPont accused the company of deliberately concealing the harm of perfluorooctanoic acid. They believe that long-term exposure to perfluorooctanoic acid may lead to neonatal malformation and cancer. Subsequently, governments and WHO have carried out a lot of research. These studies are divided into two directions.
Firstly, in animal experiments, mice were placed in high-dose perfluorooctanoic acid environment and their changes were observed. The results show that exposure to perfluorooctanoic acid does increase the risk of cancer, which may affect more than one kind, including liver, breast and pancreas.
Of course, animals are different from humans. After animal experiments, people need to be investigated. Because of ethical reasons, there are far fewer studies related to people. Some scholars have investigated the community population polluted by perfluorooctanoic acid. The data show that their serum perfluorooctanoic acid content is much higher than that of normal people. At the same time, their cancer incidence is directly proportional to the content of perfluorooctanoic acid.
After the bad news, let's talk about the good news.
First of all, the content of perfluorooctanoic acid in the serum of ordinary people is much lower than that of occupational exposure and pollution people. According to the data of National Health and Nutrition Survey 1999~2000, the average blood concentration of perfluorooctanoic acid in ordinary people was 5.2ng/mL, while the average blood concentration of residents near DuPont's Washington factory was 32.9ng/mL, and the highest among the occupational population was 6.4μg/ml, which was several orders of magnitude different.
Secondly, with the US Environmental Protection Agency (EPA) suing DuPont, since 2006, major manufacturers have agreed to control perfluorooctanoic acid, and it is planned that the factory emissions and product content of perfluorooctanoic acid will be reduced by 95% by 20 10. In 20 12, DuPont announced the discovery of a method for producing non-stick pan without perfluorooctanoic acid. At the same time, the researchers found that from 2000 to 20 10, the blood content of perfluorooctanoic acid in the general population decreased by 40%. In other words, perfluorooctanoic acid is an almost solved historical problem.
Finally, regarding carcinogens, the most authoritative one is the International Agency for Cancer (IARC). According to IARC classification, carcinogens have three grades: 1, which is obviously carcinogenic, such as alcohol, tobacco and sunlight. As long as the contact time is long enough, they will definitely get cancer; Class 2A is theoretically carcinogenic to human body, but the experimental evidence is limited and cannot be determined; Category 2B, lower than Category 2A, shows certain carcinogenicity in animal experiments, but the evidence is insufficient, and the impact on human beings is very uncertain. As of this writing, perfluorooctanoic acid is still classified as 2 B.
There must be readers who are not at ease. Even if they are not sure, it is better to have less contact. Next, let's look at the relationship between perfluorooctanoic acid and non-stick pan.
There are many kinds of non-stick pans, the most common one is coated with Teflon, and the main component of Teflon is PTFE. As the name implies, this is a polymer. In order to polymerize raw materials, raw materials must be made into solvents, and the traditional solvent is perfluorooctanoic acid. Subsequently, the surface of the pot is coated with PTFE, and then the pot is baked by the manufacturer. Ideally, perfluorooctanoic acid will volatilize at high temperature. In other words, there will be no perfluorooctanoic acid residue in the qualified non-stick pan.
In fact, because of the safety problem of perfluorooctanoic acid, China organized a large-scale investigation in 2004, and sampled 265 kinds of non-stick pans produced by 15 enterprises in five provinces and cities, including Zhejiang, Guangdong and Shanghai, but no perfluorooctanoic acid residues were detected.
So will perfluorooctanoic acid run out of the non-stick pan coating during use?
Some scholars have also studied this problem, and the results show that even under extreme heating, the perfluorooctanoic acid from PTFE is extremely low, and even if there is perfluorooctanoic acid pollution, the non-stick pan coating will not become the main pollution source.
The last question is, are there any other safety hazards in the non-stick pan?
In extreme cases, research shows that if the non-stick pan is dried for a long time and heated to 350°C, PTFE will decompose to form small particles and other gas pollutants, which will cause damage to the respiratory tract. But daily cooking is unlikely to produce such a high temperature. The smoking point of peanut oil and soybean oil is about 160℃. Even palm oil with high temperature resistance is only 230℃ in the smoking workshop. If it exceeds this temperature, the oil will smoke and decompose into complex compounds, which is harmful to the health.
In a word, the non-stick pan is safe, although it should be used carefully. Try to use a wooden spatula, try not to cook at high temperature, and it is best to replace the coating as soon as possible.
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refer to
[1]BARRY V, WINQUIST A, Steenland K. Exposure to perfluorooctanoic acid (PFOA) and the incidence of cancer in adults living near chemical plants [J]. Perspective of Environmental Health, 20 13,121(/kloc-0 ?
[2] Begley T H, White K, Honeyford P, etc. Perfluorinated compounds: the potential source and migration of food packaging [J]. Food additives and continents, 2005,22 (10):10231038.
[3]VIEIRA V. M, HOFFMAN K, SHIN H-M, et al. Perfluorooctanoic acid exposure and cancer prognosis in contracted communities: a geographical analysis [J]. Perspective of environmental health, 20 13,1(3): 3/kloc-0.
[4] The relevant person in charge of the General Administration of Quality Supervision, Inspection and Quarantine said that the non-stick pan products that meet the national mandatory standards can be safely used [J]. Supervision and Selection, 2006(03): 59.
[5] Teflon non-stick pan test evidence shows product safety [J]. Silicone fluorine information, 2006(0 1): 30.
[6] Supporting document of US Environmental Protection Agency on PFOA and PFOS drinking water health recommendations [EB/OL]. EPA, 20 16-05- 18. (20 16-05- 18)[20 19-04- 1 1]./x/2004 10 15/ 1520 1083006 . shtml？
[8] nonstick science | HowStuffWorks[EB/OL]. [20 19-04- 1 1].。 The signed articles published on this website only represent the author's views and have nothing to do with this website. If there is any infringement, you are responsible.
Author: Zhao Yanchang