5 AMAZING Facts About "The Most Dangerous Cheese in the World"

The ILLEGAL maggot cheese, also known as Casu Marzu - has been around for centuries. Here are 5 Interesting facts about this forbidden delicacy.

Maggot cheese

What is the price of a casu marzu wheel?

Nobody knows for sure.

Marketing it or serving it in restaurants is ILLEGAL: Casu Marzu is not for sale.

Is Casu Marzu safe to eat?

The European Union says no, countless generations of long-living Sardinians say yes.

"Anything good in life is either immoral, or illegal, or fattening". (F.Rand)

Let's dive in...

1. Casu Marzu has been the Robin Hood of cheeses for more than 50 years

Robin hood

The islands pecorino, serves as a base for Casu Marzu

The cheese Fiore Sardo, the "Sardinian flower", is the island's pecorino (* made from sheep milk).

This cheese that is usually the base for Casu Marzu, the "rotten cheese".

Casu Marzu
Author: Shardan

This unusual delicacy is the best of the best the lovely Italian island can offer, from a gourmet's point of view, and yet an Italian law banned Casu Marzu as long ago as.... 1962!

European regulators made matters even worse 40 years later.

The enforcing of a regulation, in 2002 made production and sales of the "rotten cheese" illegal.

Not only in Italy, but in all the common EU market.

Ironically, the name Pecorino Sardo had enjoyed a European PDO title (Protected Designation of Origin) since 1996.

In 2004, the Sardinians applied to get a PDO for Casu Marzu too, in an attempt to react to the ban.

The streets of Sardinia

Unfortunately, the authorities denied the application.

The rotten cheese is still banned though supporters hope that this will change.

And, that new rules on Novel Foods will pave the way to some solution soon.

What was the reason of the ban of Casu Marzu?


Larvae, to be precise.

The phiophila casei fly, is the minute artisan.

Piophila casei fly
John Curtis [Public domain], via Wikimedia Commons

The fly transforms a good traditional cheese like the Sardinian Pecorino in the extraordinary Casu Marzu.

Wondering how?

By eating and digesting it.

And the larvae STAY in the cheese and get to be eaten with it.


The prudery of the EU when it comes to food hygiene and safety standards is well known even on minor issues.

Live maggots in food?

No way, for EU rulers.

They regard it as an infestation.

Rotten apple full of ants

Actually, the presence of fly larvae in the Casu Marzu is not only desirable and encouraged... it is indispensable.

There would be no Casu Marzu without maggots.

As there would be no bread, wine and cheese without fermenting bacteria.

An Old Tradition

The Sardi have inhabited the island for millennia. And made pecorino from the milk of their sheep since Bronze Age.

They have a reputation for pride and stubbornness.

They proved it in this case.

The production of Casu Marzu never stopped, despite its sales being outlawed.

Several small farmers, especially in the hinterland, produce it.

Officially, only for their own consumption.

Of Course! 😉

Sardinian Street

Take from the rich to give to the poor, we could say, e.g. Casu Marzu as the Robin Hood of cheeses.

Ok, this is a romanticizing it a bit.

Today's Sardinian shepherds and cheese makers are not as poor as the Sherwood peasants.

But their rotten cheese comes from a centuries-old tradition.

A tradition of simple people and their strong connection to their land.


And now, it gets good money from gourmets and tourists with a deep pocket from all over the world.

Is Casu Marzu expensive?

As for all illegal goods, scarcity and the hazards of getting hold of it push the price of Casu Marzu up.

There are no official price lists to out there. Because, this so called black market functions on the principle "everybody knows somebody..."

Meaning that you can only get to Casu Marzu by word of mouth.

From friend to trusted friend: nobody likes EU lofty fines!

So how much does the Maggot cheese cost?

You can only find scanty information on the internet, some stating that Casu Marzu fetches at least 100 dollars per pound, some that it is only 20 Euros per kilogram...

But if you really want to find out.

Get a ferry ticket to Sardinia and start the hunt!

Production was saved from total illegality by a move of Region Sardinia.

Which listed Casu Marzu in the database of traditional agricultural Italian food products.

Which made way for an exception to sanitary rules.

As a result, the farmers can make maggot cheese... but neither they nor shops or restaurants can sell it.

So, if you want to taste Casu Marzu, find yourself a Sardinian connection to some shepperd out there....

2. Rotting is not always a bad thing

Where did the idea of a cheese with larvae come from in the first place?

There is no exact record, Sardinians have made Casu Marzu for longer than anyone can remember.

Actually it is such a simple thing, a natural process, that it must have surely just happened: an ancient sheppard found out that a wheel of cheese which had gone bad and was swarming with maggots was... delicious!

What started as an incident became technology.

Here's how it happens:

Maggot cheese

Decay of organic matter is a part of life.

But in the case of food it is usually associated with foul smells and health hazards.

When it comes to pecorino, a bit of magic takes place.

The enzymes of phiophila casei, the tiny black cheese fly, have the power to break down the fats in the cheese paste.

The flies are attracted by the strong smell of curing pecorino.

They lay their eggs in it (the farmers make it easier for them by cutting holes in the upper crust of cheese wheels and even soften it with a little olive oil).

After some time, tiny translucent white larvae hatch and start gorging on cheese.

Ready for one more yuck factor?

The yummy creamy tasty Casu Marzu is.... what the maggots have pooped!


That's right, cheese goes into the wormies, but it also has to come out. THAT way.

The texture

You should not really worry: those babies were born in cheese and only ate cheese.

The result of their labor is a soft, creamy product, more liquid than solid.

...It is actually supposed to ooze a little, producing a "tear", or lagrima to testify that the job was well done.

So you may be asking yourself...

How does Casu Marzu taste?

The taste is often described by cheese experts to resemble gorgonzola, but stronger.

Spicy, with a hint of bitterness. Lingering long in the mouth.

Fermentation alone would not be enough to start such an extraordinary transformation.

What attracts the flies in the first place is really decay.

The cheese has to start decomposing for the whole process to start.

That said, keep in mind that being processed by the maggots gives the decaying matter a new life... this is why the larvae have to be alive when Casu Marzu is consumed.

Now, you may still be wondering...

How do you know if Casu Marzu has really gone bad?

Good question...

Dead worms would be a signal that the cheese has really gone bad, and this time beyond repair.

So, look for the wriggling white wormies as a sign that you can start dipping your spoon in!

3. The Guinnes World Records awarded Casu Marzu the title of "most dangerous cheese in the world"


In 2009, the maggot cheese became the “most dangerous cheese in the world for human health”, by the Guinness World Records.

"Some who have tasted it have felt its “burn” and have even suffered from irreparable damages to their stomachs", states an articled published by Cafe Babel

The Sardinians went ballistic on this!

An italian gesture which means "What the f*ck"

The 2009 Italian edition of the Guinness Book of Records became  available in 2008.

Some representatives in the Sardinian regional council even proposed to sue the publisher!

What was the hype all about?

The danger described by the Guinness concerned the possibility that the maggots in Casu Marzu survive digestion in the human stomach... and travel further to the bowels where they could make damage.

Now, you may be curious...

Can humans really get infested by maggots?

Man in pain


An infestation of live humans (or animals) by living fly larvae is called myasis.

"Intestinal myiasis occurs when fly eggs or larvae previously deposited in food are ingested and survive in the gastrointestinal tract. Some infested patients have been asymptomatic; others have had abdominal pain, vomiting, and diarrhea" - definition by the Centers for Disease Control and Prevention, USA Government

The Guinness' claim was obviously an enormous hit at world level.

Ten years later, the definition sticks to Casu Marz and still pops up everywhere on the internet.

Associating the Sardinian speciality with the "most dangerous cheese in the world" definition.

That, and a report from 1952 are more or less all you will find –  not much to support the claim.

What you will NOT find is a serious epidemiologic study confirming or denying this claim.

Sardinians, who have been eating maggot cheese for generations beyond remembering... swear that the Guinness claims are bullocks.

And proudly boast the famed longevity of their island's inhabitants.

Old Sardinian Man

The larvae of the cheese fly do have the capability of resisting the acid environment of the human stomach up to 120 hours.

But since 1952 No reports of myasis caused by Casu Marzu consumption are known .

The infestation would mean that the maggots stayed in the intestine, not passed through... and tried to burrow into human tissue.

One small important fact: the skipper fly (* this other name of the bug is due to the capability of the larvae to JUMP!

As high as 9 inches, e.g. 15 cm., when disturbed) is about half the size of the common house fly: 4,5 mm. on average for the male and 5 mm. for the female specimen.

Jumping Larvae

The cheese "worms" are also very small, about 5 mm., with teeth smaller than a tenth of a millimeter.

They can hardly do much damage with that!

If they survive munching by cheese-eating humans in the first place.

Some other Sardinians though took the question of hygienic standards seriously.

The University of Sassari that had launched a research project already in 2005.

Their dilemma was of a different nature...

Where does all the little cheese fly pause before landing on those cheese wheels?

Man wondering

In other words, a health hazard could more probably derive from pathogens picked up by the adult flies than from the larvae themselves.

The traditional procedure of Casu Marzu making leaves it all to nature.

Where the fly has been before, what it has fed upon... no concern of the shepherds.

Yet, the possibility that they carry pathogens does exist.

The entomologies in Sassari want to create controlled conditions to breed cheese flies.

To provide farmers with "clean" maggots to inoculate their pecorino.

They hope to get rid of the bans by ensuring traceability of this unusual "ingredient".

4. British chefs made Casu Marzu even more famous.

In 2011 a couple of celebrities from the UK contributed to renewed attention for the shocking Sardinian cheese.


TV star chef Gordon Ramsay and food critic and writer Tom Parker Bowles (the son of Camilla Parker Bowles, wife to prince Charles of Wales).

Tom had to see by himself, so he packed his bags and traveled all the way to Sardinia.

A family of local farmers introduced him to the secrets of cheese making.

They involved him in the whole procedure, from milking the sheep to making pecorino... and from it Casu Marzu.

You can watch the whole report here:

Here's how Casu Marzu is being produced

1.  The first step in pecorino-making is boiling sheep milk in a big pail with rennet.

Rennet is coagulation agent. Meaning, it separates the curd from the whey.

It consists of a set of enzymes produced in the stomach of ruminant mammals.

Rennet for pecorino is being obtained from lamb or cow stomachs.

The coagulation action is fast.

About half an hour of stirring milk at temperatures of 35 C on average is enough to separate curd from whey.

Curd is then put in molds, let to drain and later cooked.

2. Adding the right amount of saltiness  

A certain number of hours in a salty solution (salamoia) are required as part of the process.

When making Casu Marzu this has to be kept to a minimum.

Because, too salty a pecorino would discourage flies from laying their eggs in it.

Also, the wheels of cheese are not turned ever so often as they usually would.

3. Then it's up to nature, and time.

The flies will find their way to the cheese, and with a little help from the humans (* the holes in the crust), into it.

Up to three months of maturing are needed for them to do their work.

Cazu Marzu production in seasonal


It has to keep into account the life cycles of both sheep/lambs and of flies.

The insects need warm temperatures (at least 25 C, though they can endure twice as much).

Which makes this activity a spring and summer business.

It goes down well with allowing the sheep to milk their baby lambs.

Cheese making can happen approximately between May and October, in natural conditions.

Tom's adventure in Sardinia includes taking part in a traditional family lunch party.

With lots of guests of all ages and gorging Casu Marzu in company.

Along with many glassed of strong red Cannonau wine.

That is absolutely realistic, e.g. the way the whole business happens in Sardinia.

Change of scene and away to the tv set of "The F Word" with Gordon Ramsay.

Ramsay makes a show of eating the Sardinian outlaw delicacy, maggots and all, in front of cameras.

Boy, that WAS a hit (more than a million hits, in fact)!

So, two years after the dubious glory received by the Guinness stunt, Casu Marzu was on the stage once more.

No doubt this contributed to even more foreign tourists and foodies scouting the Mediterranean macchia in search for the forbidden gourmet treasure.

5. The university of Wageningen has done research on the "Unsafe Casu Marzu "

Science illustration

There is more to the story of Casu Marzu than sensationalism.

A recent master thesis at the prestigious Dutch University of Wageningen was discussed in Februrary 2018, on the question:

"Can Casu Marzu be deemed safe according to article 14 of Regulation (EC) No 178/2002? "

The author, Yvette Hoffmans, presented the case on as many as 80 pages.

"In the beginning of 2017, an evening course called Insects and Society crossed my path. During this course, I learned about the wonderful world of insects and showed me how beneficial insects can act as food and feed. Casu Marzu was one of the examples of insects as food consumed within the European Union", Yvette explains in the preface.

We are talking about serious official research here, as stated in the document:

"Thesis is an obligatory part of the master programme Food Safety Law at the Wageningen University. This thesis is conducted at the chair group Law and Governance. "

Why is this thesis a very useful reading not only for the aficionados of Casu Marzu?

But also for entomophagist in general?

Because the author has hit a very hot question spot on:

What is considered acceptable/legal by the European Union... when it comes to the health safety requirements to put specific put products on the market?

The basic research question of the master thesis is:

Can Casu Marzu be deemed safe according to article 14 of Regulation (EC) No. 178/2002?

An illustration of a document

Apparently simple, right? Not so.

"Article 14 of Regulation (EC) No. 178/2002 says that food shall not be placed on the market when unsafe. The same article furtherly explains that unsafe can either be injurious to health or unfit for human consumption and how these definitions should be determined in relation to food products."

In a couple of lines you get a concentrations of concepts that are actually quite complicated to interpret.

So much so that the author breaks them down in three distinct chapters.

The three chapters

  1. A whole analysis of the EU legal background (involving several EU regulations),
  2. A comparate study of other foods presenting potential risks hazards even more than Casu Marzu (though they have been on the market forever)
  3. A discussion of what makes a food "fit" or "unfit" for human consumption.  Describing, what you can learn if you can bear through dozen of pages packed with information.

As you see, Casu Marzu could be quite important for the future of entomophagy, if put under the spotlight in the correct manner.

Not as a curiosity, something weird that wild Sardinians do (eat) on their far away island.

Casu Marzu is a brilliant example of the clash between centuries-old tradition and modern food safety worries.

And the star of the show is... an insect.

So, after reading all of this, you're probably wondering...

Is Casu Marzu safe?

Cucumber wrapped in plastic


But we're not in the position to give you an answer.

Perhaps, these two snippets from the above mentioned study will guide you in the right direction.

One can notice from the comparison study that Casu Marzu can pose risks, but that other products, widely marketed within the EU, can pose risks as well. The major risk in larvae, is unlikely to occur in the case of Casu Marzu. Besides, some hazards identified in Gorgonzola, oysters and mushrooms can easily pose a risk for its consumers, since dose-response or the legal limit is approached.

In the last section of the study, Ivette wrote:

I see possibilities in the future for a safe Casu Marzu with the implementation of Regulation (EU) No 2015/2283. Since 2018, insects are considered as novel food. This would make marketing of larvae possible throughout the EU. Rearing the larvae under monitored conditions for the purpose of using it as raw material in Casu Marzu would be a solution to consider.

Now, I'd like to hear from you...

What do you think about Casu Marzu? 

Would you there to try it if it would be legal? 😃

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