Edible oil, especially the residual crude oil, contains more plant residues, which may lead to rancidity of oil. Cooking oil contains a kind of linoleic acid, which easily reacts with oxygen in the air. This phenomenon is called "oil oxidation". A series of reactions, such as oil and fat hydrolysis, can produce oxides, peroxides and other decomposition products of small molecules such as aldehydes, ketones and carboxylic acids with special smells. The pungent taste is the result of oil oxidation and rancidity. After rancidity of oil, it is smoky and choking when heated, which contains decomposition products such as epoxypropanal, which is easy to be poisoned after eating.

There are three toxic effects of rancid oil acute poisoning:

First, the direct stimulation to the gastrointestinal tract. That is, after eating, nausea, vomiting, abdominal pain, diarrhea and so on appear one after another.

Second, toxic substances such as peroxides produced by deteriorated oils transform hemoglobin bivalent iron into hemoglobin trivalent iron, and its toxic effect makes hemoglobin lose its oxygen-carrying function, resulting in hypoxia of the body, resulting in cyanosis of mucosa and skin.

Third, the oxidation of rancid substances affects succinate oxidase and cell color in the enzyme system of the body ...