Typical dimples or divots caused by the grown of Scopulariopsis on the surface of a natural rind cheese. Left unchecked, the fungus can bore into the paste of the cheese causing discoloration and allowing for the proliferation of cheese mites.

Microbe Guide: Scopulariopsis

When I first met Sister Noella Marcellino, the artisan cheese maker and advocate who is the star of the documentary The Cheese Nun, she enthusiastically declared that Scopulariopsis is one of the most important, but also most poorly understood molds in artisan cheese. Four years later, after observing hundreds of cheese rinds and thousands of isolates of cheese molds, I wholeheartedly agree with Sister Noella. This mold is incredibly widespread, often well-behaved, but sometimes causes severe problems for cheesemakers.

 

Here’s a guide to what you need to know about Scopulariopsis.

Macro- and microscopic appearance:
On cheeses, this fungus creates flat dusty or felt-like patches of brown, white or purple. It can also create contiguous felt-like rinds that are white or brown in color. When growing in the lab on standard lab media, Scopulariopisis forms colonies that range in color from white to brown to purple.

Brown Scopulariopisis shouldn’t be confused with the mold Mucor. Mucor has a much more raised and fuzzy appearance and will never appear flat and dusty on the surface of a cheese.

Scopulariopsis growing on a bloomy rind (left) and natural rind (middle) cheese. A closeup view of both white and brown Scopulariopsis growing on the surface of a natural rind cheese. Photos by Benjamin Wolfe.

Scopulariopsis growing on a bloomy rind (left) and natural rind (middle) cheese. A closeup view of both white and brown Scopulariopsis growing on the surface of a natural rind cheese. Photos by Benjamin Wolfe.

Under the microscope, distinguishing features of this mold are conidia (spores) with a clear ‘scar’ (A in the image below) where they used to be attached to a conidiophore (B in the image below). This beautiful set of time lapse images shows how the conidia form.

Brown (left) and white (middle) colonies of species of Scopulariopsis isolated from cheese rinds. These colonies were grown on Petri dishes in the lab. Each colony is about 3 cm wide. On the far right is a microscopic (1000X magnification) view of the spores of Scopulariopsis. The letter A marks detached conidia. B indicates a conidiophore. Photos by Benjamin Wolfe.

 

Food habitat:
Scopulariopsis is widespread on natural rind cheeses and can sometimes be found on the surfaces of salame. It seems to prefer food surfaces that are drier and where there has been prior colonization by other molds, especially Penicillium species.

Scopulariopsis is incredibly widespread in the environment, so it’s very hard to keep it out of food production and aging facilities. It can live in association with mammals, insects and in soil. Some dairy scientists have suggested that one of the main routes of entry in food production facilities is through paper packaging products.

 

Impacts, Functions, and Management:
One of the biggest potential problems that Scopulariopsis can cause on cheese rinds is boring into the paste. Many species and strains of this mold are highly proteolytic and can quickly break down the protein in the curd of a cheese. As they do this, they may create divots or burrows that could ultimately discolor the cheese curd and destabilize the rind.

Typical dimples or divots caused by the grown of Scopulariopsis on the surface of a natural rind cheese. Left unchecked, the fungus can bore into the paste of the cheese causing discoloration and allowing for the proliferation of cheese mites. Photo by Benjamin Wolfe.

Based on my experience growing this mold in the lab and smelling the rinds of many cheeses, this fungus definitely produces a sharp musty smell. It’s almost slightly fruity or fresh compared to the more deep and earthy aromas produced by other molds such as Penicillium.

One way to decrease the growth of Scopulariopsis on the surface of cheese is by periodic washing. This will break up the mycelium of the mold and prevent it from further colonizing the cheese surface. Washing will also favor the growth of fungi and bacteria that prefer moist conditions.

 

Have you had any interesting or frustrating experiences with Scopulariopsis? Tell us about them in the comments section below!

 

Post written by Benjamin Wolfe. 

 

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