Healthy Living from Oil | Can we still eat cooking oil that has a “rancid” smell?

Cooking oil, cakes and other foods will produce a bitter, pungent and unpleasant smell after being stored for a long time, commonly known as "rancid" smell. Cooking oil and food with "rancid" smell have gone bad and cannot be eaten.

The "rancid" smell is caused by the rancidity of fats. The rancidity of fats in edible oils and foods is affected by many factors, such as the degree of fatty acid saturation, light, and moisture. Under the action of high temperature, light, or microorganisms, fats will decompose into glycerol and fatty acids. Fatty acids will further decompose into carboxyl compounds such as ketones and keto acids, giving rancid oils a "rancid" smell. When heated, edible oils with a "rancid" smell will produce a lot of smoke and choke people, and will decompose to produce glycidaldehyde. Glycidaldehyde, also known as glycidaldehyde, is a moderately toxic substance. After consumption, the following discomfort reactions may occur: ① Nausea, vomiting, and abdominal pain; ② Cyanosis of mucous membranes and skin; ③ Acute respiratory and circulatory failure.

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