"I need to know that my food's not rotten"

Surrstromming!

http://www.visitsweden.com/sweden/Things-to-do/Swedish-Lifestyle/Swedish-traditions/Food-Fermented-herring/

Yes, there is a fine or maybe blurry line between fermented and rotten. Aged beef, stinky cheeses, aged salami, wine, vinegar, yogurt… I like Eppoisses which could be considered rotten, but not durian, which only smells like it is!