Swedish canned herring (Surstromming) is a traditional Swedish food. It is a canned food with bad smell and sour taste. It is made by putting the processed herring into a can and letting it ferment naturally.

The biggest feature of fermented herring is its ubiquitous and persistent stench. People who have never eaten pickled herring often cover their noses because of its pungent smell. It is reported that the Swedish government also stipulates that it is not allowed to open canned herring in residential areas. International flights are also not allowed to carry this kind of canned food, because the change of air pressure may lead to the rupture of canned food, with serious consequences. Its smell is 300 times that of natto.