Casu Marzu:
Derived from Pecorino Sardo, casu marzu goes beyond typical fermentation to a stage most would consider to be decomposition, brought about by the digestive action of the larvae of the cheese fly, Piophila casei. These larvae are deliberately introduced to the cheese, promoting an advanced level of fermentation and breaking down the cheese's fats. The texture of the cheese becomes very soft, with some liquid (called "lagrima", from the Sardinian for "tears") seeping out. The larvae themselves appear as transparent, white worms, about 8 mm (1/3 inch) long. When disturbed, the larvae can jump for distances up to 15 cm (6 inches), prompting recommendations of eye protection for those eating the cheese. Some people clear the larvae from the cheese before consuming; others do not.
Appearance and taste Yaroslav Trofimov, writing in the August 23, 2000 edition of The Wall Street Journal, describes the cheese as "a viscous, pungent goo that burns the tongue and can affect other parts of the body". Susan Herrmann Loomis reports an encounter (in a 2002 Bon Appétit article):
He … grabbed a piece of pane carasau, the traditional flatbread of Sardinia, rinsed it quickly under water to soften it and went to a large glass jar on a side table. He opened the jar, scooped out a mound of what looked like thick cream, and folded the bread around it. …When he was finished I asked what he had eaten, and he got up to show me. Inside the jar was pecorino, busy with small, white worms. I'd heard about this cheese, but this was the first time I'd gotten so close. … A friend of his … said, 'It's formaggio marcio [literally, "rotten cheese"], cheese with worms. It's a delicacy. It's the most beautiful gift you can give a Sardinian shepherd.'
The cheese is typically consumed with Sardinian bread (pane carasau) and Cannonau, a strong red wine.