Olive oil

Fake versions of olive oil are extraordinarily common, with retailers passing off other seed oils, including soybean oil, peanut oil, and sunflower-seed oil, as the real thing.

Consuming fake olive oil can have serious health consequences, such as a 1981 case in Spain where 20,000 people consumed so-called olive oil that was in fact rapeseed oil, containing a poisonous toxin called aniline.