It’s Spooky, It’s Creepy, and It’s Totally Awesome and Is Really Good For You Too! What is It? Read and Find Out!

HalloweenMoldHero.pngWith Halloween just around the corner, we thought it would be apt to zoom in on one of our favorite subjects in the cheesy galaxy we inhabit – MOLD! We live in a society where mold is anathema – if something has mold on it, the conventional wisdom of the day (that is 2016, mind you, in 1916 that outlook was likely much different) says to put on the biohazard suits, run for the hills, and dispose of said moldy product in the most expeditious manner possible.

But we cheesemongers beg to differ! We are awash in a world of fascinating (and delicious) bacteria, mold and yeast that make our heads spin with wonder and our bellies contented with nutritious cheese. Our guts are probably happy about it too… it’s been proven by scientists (and touted by ‘real’ food titan Michael Pollan) that probiotics in food help nourish the gut’s microbial population making it easier to digest food and arguably making us healthier overall. Bottom line is this – humans have had a wonderfully symbiotic relationship with mold over the millennia, and we’re here to celebrate the artistry of our microbial colleagues that aid in the flavor development of cheese – from the cheese vat to the aging cave to your dinner table.

All cheese is mold…

Sometimes people freak out at our cheese counter when they see a spot of blue or green or gray mold gracing the rind of their cheese. What they can’t see are all of the other microbes that have gone into the development of the cheese from the cheese room to the cheese counter.

Milk is inoculated with different bacterial cultures at the outset of cheesemaking to start the fermentation process and lay the cornerstones of flavor for the finished cheese (starter cultures). The bacteria consumes the lactose (or the sugars) in the milk and produce lactic acid as a byproduct. Additional types of bacteria might be used to jumpstart the development of flavor in cheese later in the ripening process (secondary ripening cultures)

All of the strains of bacteria used in starter cultures have been isolated over humanity’s thousand-plus year love affair with cheese for their flavor producing properties. And different types of culture produce different flavors in cheese… cultures used to make say, a brie-style cheese differ greatly from cultures used to make a cheddar-style cheese. Nobody knows exactly how many different types of bacteria there are in the world, but today’s scientists are putting their conservative estimate at over one trillion. Of course not that many are used in cheesemaking, and not all of these bacteria are good for us, but in the battle of good versus evil, we cheese folks are working with the superheroes of the bacterial world.

After the cultures have done their work to start milk’s ‘leap towards immortality’ as cheese, then the molds, yeasts, and (even more) bacteria take over. When cheese is ripened, different molds, yeasts and bacteria colonize the rind and sometimes the interior of the cheese itself (in the case of blue cheese) causing different cheeses to have different appearances.

Bloomy rind cheeses are home to scores of mold and yeast that literally ‘bloom’ on the surface of the cheese, blanketing the exterior in a downy white rind comprised of bajillions of mold and yeast organisms.


Natural rind cheeses are salted and left out in the cave to attract and encourage any ambient mold present in the environment. Michael Lee’s goat and cows’ milk cheeses from Twig Farm may be our favorite incarnation of the natural rind phenomenon. Their thick gray fuzzy rinds are a singular work of microbial genius.



Washed rind cheeses are brushed with different liquid solutions – from salt brine to booze depending on the cheese – to encourage bacterial growth on the exterior of the cheese. Old school, dyed in the wool American cheesemakers sometimes refer to this process as ‘smear’ ripened. Sounds kind of yucky but kind of awesome all in one go!



Blue cheeses are inoculated with different strains of mold stemming from the family ‘Penicillium Roqueforti’. Legend has it that blue cheese was a happy accident caused by a cheesemaker who left a moldy loaf of rye bread in his cheese room whose spores got into his cheese. Contrary to popular belief, blue cheeses are not injected with blue mold. The cultures are mixed into the milk during cheesemaking, and are activated when the cheesemaker pierces the wheels of cheese with stainless steel needles. The oxygen allows the mold to grow, creating the blue veins that we see in blue cheese.


Pearl with blue mold_600px.jpg

Definitions / What The Heck Does This All Mean?!?

Bacteria – microscopic organisms, usually single-celled, that can be found everywhere. They can be beneficial, such as when used in fermentation of foods, or to aid in the decomposition process, or dangerous, such as when they cause infections.

Mold – multi-celled organisms that are part of the fungi family. They are aerobic (i.e. need oxygen to grow). Molds have a long, threadlike shape, produce spores, and can be found in many colors – orange, green, black, brown, pink, or purple.

Yeast – one celled organisms that that are part of the fungi family. They are not as colorful as mold; most yeasts tend towards a white or off-white color. They are anaerobic (i.e. do not need oxygen to grow) and do not produce spores. Yeast is also found everywhere.

Probiotics – live microogranisms (bacteria and yeast) that, when administered in proper amounts, provide a health benefit to the host. (i.e. yogurt with ‘live cultures’ or any cheese for that matter!)

Saxelby Cheesemongers’ Mold FAQ’s

Q: What molds are edible vs inedible?

A: All of the mold on cheese is technically edible. However, there are certain kinds of mold that are less desirable. For example, pink mold on a bloomy rind cheese is not desirable – it is an indication that the cheese was a bit too damp at some point in production. Blue or gray or greenish mold on the surface of a bloomy rind cheese is totally fine to eat, and will not influence the flavor. Surface mold on a cut piece of cheese is technically edible (i.e. it will not kill you or make you sick) but should be trimmed away for best flavor.

Q: What should I do if mold grows on my cheese?

A: All cheese is dependent on different bacteria and mold to ripen it and develop its flavor… In the world of cheese we LOVE mold! Should any mold develop on the cut surface of the cheese, don’t worry, and DON’T throw the cheese away! Simply trim away the surface mold and then keep on enjoying that glorious wedge!

Q: Can I eat the rind?

A: YES! Unless the cheese is wrapped in wax or cloth, the rind is edible. The rind is to the cheese what crust is to bread. With softer bloomy rind cheeses, the rind really enhances the flavor. With more aged cheeses, the rind can be quite dry, hard, earthy, etc. Try it for yourself – if you like it, eat it, if you don’t, trim it away.

Q: Can the mold on cheese be a problem for people with allergies?

A: There are some penicillin-based molds in cheeses – mainly bloomy rind cheese and blue cheese. However, a person would have to have a VERY strong allergy to have a reaction to the cheese. The worst we’ve heard of is people having a slightly itchy sensation in their mouths or tongues.




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