You slice into a wheel of perfectly aged pecorino, peel back the top, and find a wriggling mass of maggots. If it’s casu marzu, all is going according to plan.
From the Sardinian for “rotting cheese,” casu marzu is the product of larvae-driven fermentation. Cheesemakers initiate the process by cutting a small hole in a wheel of sheep’s milk cheese and leaving it outside. Flies—Piophila casei, to be exact—slip in through the opening and lay eggs. After the larvae hatch, their excretions break down the cheese’s fats and proteins, creating a soft, creamy texture.
When gooey liquid known as lagrimas (“tears”) leaks through the rind, it’s ready to eat. The resulting cheese is pungent and sharp, a bit like ripe gorgonzola, with an acidic twang left in the larvae’s wake.
Even though the creamy hunk of cheese might look tempting, approach with caution. As The Science of Cheese points out, “Cheese skippers [maggots] are able to jump a few inches, so consumers are advised to protect their eyes” when unsealing the wheel.
Sure, a maggot to the eye would be unfortunate, but the larvae can do far more damage to your insides—including pain, nausea, and vomiting—if they’re alive when eaten. But you can’t just buy cheese with the maggots already dead; that’s a sign it’s gone bad. The solution? Plenty of people take the risk and eat live maggots. Alternatively, mash them to death and smear the cheese on pane carasau, a type of flatbread. Or seal a piece in a zipped plastic bag. When the sound of pattering maggots stops, it’s snack time.
While casu marzu is the most famous maggot-infused cheese, it’s not the only one. Elsewhere in Italy, there’s marcetto in Abruzzo, casu du quagghiu in Calabria, saltarello friulano in Friuli, and cacie’ punt in Molise. Not to be outdone, French cheesemakers offer their own take, casgiu merzu, in Corsica. So even if you can’t get your hands on casu marzu, there are plenty of opportunities to get some grub.
Need to Know
Casu marzu's legal status is murky due to health risks, so you’ve got to do some sleuthing to find it. A simple inquiry at a Sardinian cheese shop usually leads seekers in the right direction. In a 2017 article for Food & Wine, a reporter scored some casu marzu at a panini truck run by a “Signor Francesco” near the Sardinia airport.