anti-oxidant

Any substance that prevents deterioration of fats, oils, paints, plastics, and rubbers by oxidation. When used as food additives, anti-oxidants prevent fats and oils from becoming rancid when exposed to air, and thus extend their shelf life.

Vegetable oils contain natural anti-oxidants, such as vitamin E, which prevent spoilage, but anti-oxidants are nevertheless added to most oils. They are not always listed on food labels because if a food manufacturer buys an oil to make a food product, and the oil has anti-oxidant already added, it does not have to be listed on the label of the product.

They are limited to 0.02% of the total content by FDA standards.