One of the most harmful and disgusting counterfeit products ever encountered is so-called “gutter oil”—so named because it is cooking oil that is made from sewer refuse, left-over oil from restaurant fryers, and rotten animal fat or slaughterhouse waste. Nearly all of it is produced in China and is often sold to small restaurants. At one time nearly one-tenth of China’s cooking oil was gutter oil.
Gutter oil was first discovered in 1985 in Taiwan. Twenty-two people were arrested for involvement in a recycling oil ring. Reprocessing and filtration of gutter oil was primitive, mostly boiling and skimming off of larger adulterated matter.
The Chinese government initiated a nationwide campaign in 2011, which led to the shutting down of about one hundred manufacturers. Continued enforcement has led to other arrests. The Taiwanese police arrested a man named Chang Guann, a major lard supplier in 2014. Guann had purchased over 200 tons of gutter oil and sold it throughout Southeast Asia.