Casu marzu is rotten cheese with fly larvae. This cheese is traditionally made of sheep milk in Sardinia. It is peculiar for being made with the help of cheese flies and containing live larvae of these insects.
It is currently prohibited to sell this cheese. But Sardinian farmers continue producing it for local needs and consuming it.
The preparation of Casu marzu begins with cutting off a small part of the crust from Pecorino Sardo sheep milk cheese. Thus, cheese flies get an easier access inside the cheese and lay eggs there. The insect larvae eat through the cheese, digest fats, and the cheese becomes very soft.
Before the cheese is ready, it accumulates thousands of whitish translucent larvae up to 8 mm, which can jump to the distance up to 15 cm. When Casu marzu is ready, it produces special liquid – lagrima, i.e. “tear”. After 3 months, the entire core of the cheese becomes pasty. Cheese readiness is determined by the activity of the larvae. It is not difficult to notice, as the cheese is literally crawling with them.
The soft inside of the cheese is served with thin Sardinian bread (pane carasau) in the form of flat cakes. Locals spread Casu marzu on one piece, cover it with another piece (for the larvae not to get into the eyes), and wash it down with strong red wine.
Local residents say they live long because of this cheese. It is not clear if it is true. However, Sardinia really has many long-lived people; some of them are 100 years and more. This delicacy is very popular among the Sardinians, despite its danger and possible trouble. Its price is three times higher than the conventional Pecorino.
Local producers dream of legalizing the cheese. They want to breed sterile flies that will not bring possible pathogens from the outside.