What Are Cheese Mites?

Sometimes Good, Sometimes Bad, They Love Your Cheese

Block of mature cheddar cheese.
J Shepherd/Photodisc/Getty Images

At a cheese shop, the owner tapped some powder off the surface of a piece of Mimolette into a small glass bowl and handed me a magnifying glass. I saw a bunch of crumbs moving constantly, tiny specks that sometimes jumped. “ Ce sont des cirons,” — cheese mites — he told me. “Small spiders that live in the cheese.” I was curious, and a little repulsed.  

The Definition of Cheese Mites

Cheese mites are microorganisms that exist everywhere, but they especially love the damp, cool atmosphere found in the cave d’affinage, or cheese-aging chamber.

They flock to cooked, pressed cheeses like Comté, or Cantal, boring into the crust, moving steadily towards the softer center, leaving behind a floral, sweet flavor. If left to their own devices, the artisons will take over a cheese until it becomes inedible. Many hard cheeses are, in fact, treated to deter cirons — the rind of Parmesan, for example, is oiled; cheddar is traditionally wrapped in cloth.

A Brownish Dust

Cheese mites are so tiny that the naked eye can't usually detect them. Their presence is detected by very fine brownish dust on a wheel of cheese. A joke among cheesemongers is that if you brush the "dust" off the rind of a wheel of cheese and a few hours later the "dust" has moved to a new location, you know the cheese has been infested by mites. 

This "dust" is really an accumulation of living mites, dead mites, mite excretion (poop), and cheese debris. It sounds unappetizing but is really quite harmless, unless you have a severe allergy to mites.

Mites are present in all different types of dry goods, like grains and flours, without causing direct harm to humans.

Mites tend to be present on the outside of hard cheeses, such as Cheddar and Mimolette. Usually, the mites can be brushed off the rind of the cheese without affecting the flavor of the cheese inside.

Some people even think that mites give cheese more flavor, which is the case with Mimolette.

Mimolette and Mites

There is one French cheese, however, that welcomes these microscopic creatures — uses them, even — as part of its aging process: Mimolette. Produced in Lille, near the Dutch-Belgian border, it’s a hard, orange cheese (similar to Edam) with a thick crust riddled with holes. Mimolette starts out like any old pressed cheese, but at one or two months old, it’s taken to a special chamber and inoculated with artisons. They nibble relentlessly, burrowing into the crust, aerating the cheese, and dramatically reducing the mimolette’s bulk. The result is a dense, salty cheese, with earthy, sweet, almost caramel, undertones. Alas, for American cheese lovers, aged mimolette was banned by the FDA, who declared the excess of mites an allergen and health hazard.

Mite Intervention

One of the key factors in limiting mite damage is early intervention, such as brushing or vacuuming (both must be done regularly to have significant effect).  Once the mites work their way under the surface of the cheese they gain a measure of protection from any attempts to disrupt them.

For an interesting story about cheese mites, listen to this podcast of the radio show "Good Food" in Los Angeles called "Cheese Mites: Pests or Flavor Enhancers?"