China has a known problem with "counterfeit" cooking oil made illegally by gangs. Not just inferior cooking oil relabelled as well-regarded brands, but made from waste oil and rotting animal parts.
This is generally known as "gutter oil" (Chinese pinyin
dìgōu yóu, simplified characters
地沟油, traditional characters
Gutter oil can contain bleaches and chemicals to alter its colour and pH level to more closely resemble cooking oil. These include known carcinogens.
People caught running such rackets have recently received very harsh prison sentences but a reliable method for detecting gutter oil had not been found last I checked.
I'm quite a foodie when I travel but I'm still on a low budget so I eat where the local people eat. Cheap restaurants, stalls, and especially street food.
There's always some risk when you choose to eat street food. But generally you expect just low hygiene standards. I certainly did not expect to be eating food adulterated with cancer-causing ingredients by organized gangs!
So is gutter oil also known to be a problem elsewhere in Asia, or elsewhere in the world? Or is it a strictly Chinese invention?
Do travellers have to worry about adulterated food when overseas now? This is beyond the usual expectations of food poisoning!
Just to be clear, because it seems some people have misread, this question is asking about this issue in other countries. Not about other issues in this country. I added the China tag because that's where problem is known to exist, for comparison.
Just to be clear, this is just about "gutter oil", which is a dangerous fake product tourists can consume without knowing it. It's not about other fake goods or even about re-labelled fake cooking oil. Please read the Wikipedia article on gutter oil if you are like Andrew Ferrier and think this is "irrelevant to travellers"!