The commonly used flour whitening agent is benzoic acid peroxide, which has a significant effect. Generally, the amount of peroxybenzoic acid is not more than 75ppm (ppm is one part per million), but some manufacturers have used more than 100ppm, which is why our common flour looks white. Let us take a look at the harm to the human body when the whitening agent of flour is added.

　　 1. Peroxybenzoic acid is hydrolyzed to produce benzoic acid, which is detoxified by the liver in the body. Excessive intake is harmful to the liver. In severe cases, it can cause purpura on the skin. Brighteners can also destroy the nutrients in the flour, reduce the body's absorption of vitamins, and cause angular cheilitis, neuritis, keratitis and other diseases.

　　2. What's more, some unscrupulous manufacturers have added prohibited "hanging white pieces" to flour and pasta products. The chemical name of the hanging white block is sodium formaldehyde sulfoxylate, which is an industrial bleaching agent. As long as people ingest 10 grams, they will die. Some people use talcum powder and industrial calcium phosphate as the carrier of whitening agents; some even add formaldehyde, which will cause harm to the human body.

　　3. Another thing to mention is potassium austerate, which is a flour treatment agent that can strengthen gluten, toughen and swell. In the hygienic standards for the use of food additives, potassium laurate in flour shall not exceed 0.3%, and it is required that potassium bromate cannot be detected in flour. However, many flour manufacturers have not implemented this. In recent years, it has been found that the use of potassium austerate is often exceeding the standard. It is important to know that excessive consumption of potassium diannate can damage people's blood and kidneys. And to some extent, it may cause carcinogenesis, and it has been listed as carcinogen, which should arouse people's general concern.

　　 Therefore, from the above introduction, we can see that there are many hidden dangers in flour. When choosing flour, consumers should know that the whiter buns are not the better. When the buns are too white, we should be vigilant and try not to buy them.