Traditionally, vegetable oils are “extracted”. Therefore, when consumers hear that some of the oil is “leached” with “toxic” chemicals, the instinctive feeling is that “this stuff must not be safe”. And a tea oil leaching varieties were exposed to “carcinogens” exceeded the standard, more so that the public doubts about this “non-traditional” process has reached a new height. What are the carcinogens in tea oil? Why the traditional “pressed oil” is not, but the “leaching oil” exceeds the standard? In fact, the “leaching method” of vegetable oil is now the international mainstream. In developed countries, there are few traditional “pressing” plants. So-called “leaching” involves “soaking” the crushed oil seeds in a very volatile organic solvent, most commonly hexane (or a hexane-based solvent mixture). oil seeds. Because vegetable oils have a stronger affinity for these organic solvents, almost all of the oil can run into the solvent. After separating the solvent-oil mixture from the oil residue, the solvents are removed with a little heat, resulting in “crude oil. The “crude oil” is further purified and refined to give a pure and clarified vegetable oil. Although it is true that organic solvents such as hexane are toxic to some extent, they hardly remain in the oil because they evaporate so easily. According to the U.S. Environmental Protection Agency’s safety standards for n-hexane, and the possible residues of n-hexane in leached oil, a person eating dozens of pounds of leached oil per day would not reach harmful amounts. Compared to the “press” method, the “leaching” method requires more complex equipment and processes, but the advantages are obvious. Leaching extracts almost all of the oil from the oilseed, whereas pressing only yields 70 percent or less depending on the specific oilseed and pressing process. For food, such a difference can be considered revolutionary. The “carcinogen” in the “tea oil carcinogen exceeds the standard” incident is called “benzo(a)pyrene”. It is actually not a product of modern industry. The combustion of any organic material will produce benzo(a)pyrene. So, when our primitive ancestors learned to roast meat over fire, humans began to ingest benzopyrene. Even in natural water sources, benzo(a)pyrene may be present in some amount. Benzo(a)pyrene is a recognized carcinogen, and high concentrations of benzo(a)pyrene can induce cancer. As for the relationship between human intake and cancer risk, there is no clear scientific data. However, because it is not of the slightest value to the human body and people may ingest it from various sources, the authorities’ requirement is the lower the better. For example, the U.S. drinking water standards in the benzo(a)pyrene “target content” of zero. However, because of its widespread presence in nature, the goal of zero is not achieved. The U.S. government has set a “practical control standard” of no more than 0.2 micrograms per liter of water. It is estimated that a lifetime of drinking water containing this concentration of benzo(a)pyrene would increase the risk of cancer by roughly one in 10,000. The safety limit for benzo(a)pyrene in Chinese cooking oil is no more than 10 micrograms per kilogram. Considering that the amount of oil people eat every day is only a few tenths of the amount of water they drink, this “safety standard” is still reasonable. According to news media reports, the benzo(a)pyrene in tea oil exceeds the standard is actually the result of manufacturers’ irregularities. In order to maximize the extraction of the last drop of oil, manufacturers of oil residues repeatedly heated at high temperatures. Any organic matter may produce benzo(a)pyrene at high temperatures, and the oil residue is naturally no exception. Finally, these benzopyrene was “leached” into the oil, so there is a benzo-pyrene exceeds the standard of tea oil. Obviously, the “leaching method” itself does not produce carcinogens, and the tea oil itself does not contain carcinogens. More than the national standard permit benzo(a)pyrene, is the result of the manufacturers to increase the yield without regard to product quality. The solution to the problem is not the rejection of tea oil (of course, its false propaganda and very low cost performance is another matter), not the rejection of “leaching oil”, nor the return to the traditional oil extraction workshop, but – manufacturers of reasonable and standardized production processes, as well as the competent authorities The competent supervision.