Tonight I went to grab the grated parmesan I bought at Whole Foods last week for my manicotti and was shocked that it had turned blue and smelled funny. I just bought this parmesan within the past week and it has been stored in the cool, dark, dry cabinet that I store all of my spices.
I didn't think that parmesan would turn moldy like that. It has NEVER happened to me before. All of my parmesan has kept seemingly forever (or until I consume it).
I am baffled...anyone have an explanation??

Could be contamination from a blue mold cheese like Roquefort or Stilton.

Why don't you keep your cheese in the refrigerator? Just curious . . . .

I keep all of my cheeses in the fridge except for parmesan because I really thought it was shelf-stable. I just never have known it to go bad or mold.
So, maybe another type of cheese got mixed in with the parmesan at Whole Foods??

I think any parmesean, except maybe the kraft in the can. needs to be refrigerated. As I recall, my mother refrigerated the green can as well!

1) Whether you bought the pseudo Parmesan produced in Argentina or Wisconsin or Parmigiano Reggiano, the cheese needs to be refrigerated. Now you know. Believe me, you're not the only one Kraft and its preservatives led on the path of false security.

2) On the behalf of the Italian People and the proud producers of Parmigiano-Reggiano parading around the perimeters of the piazza of the cathedral in Parma in particular, the Virgin Mary is punishing you for purchasing grated Parmesan.*

Pick up a chunk of the real deal next time. Hand-held graters cost little at T.J. Maxx and $11 for a MicroPlane at Linen & Things with a coupon.

*Proof? Do a google image search. Blue's her color.

Yeah, or maybe bread mold migrated to your cheese, or maybe somebody at the store didn't wash their hands after they cut some bleu cheese, or (even worse) after they went to the bathroom.

I did that one time, got up early and made breakfast for some people who were leaving early, didn't wash my hands first, and a day or two later when I wanted to use the bacon, I could see four parallel fingerprints on the bacon, outlined in mold - can't remember the color of the mold, it might have been blue, green, pink or yellow, but will never forget the image.

I was just thinking that the last time I purchased grated parmesan it was from Trader Joe's. That parmesan held up fine in the cabinet with my spices. Does that mean that TJ's parmesan is comparable to a canister of Kraft?

AB, I will look into my own parmesan grater...I consume a LOT of parmesan.

Apparently.

It's cheese, dude (well, maybe not the Kraft or whatever it is you got at TJs). There should be no preservatives added to make it "shelf stable". Get a hunk of reggiano and a micro-plane. Sometimes I use a vegetable peeler instead for big shavings. Throw the cheese in a ziplock and put it in the fridge. In no time you'll have a $30/month reggiano habit like we do in the Dente household.

If you're going through a lot of it fairly quickly, that's possibly why you've managed to keep it unrefrigerated and not notice mold before. I always refrigerate Parmesan, even the green cannister kind (Doesn't it say on the can that it should be refrigerated after opening? I haven't bought any in quite some time, but I thought I remembered that.)

I was at Trader Joe's this weekend. The Parmesan in big cardboard cylinders is exactly like the Kraft stuff. The company figures that many of its consumers don't know the difference between Kraft and Parmigiano-Reggiano and just want what they grew up shaking onto their pizza.

However, TJ's also sells real Parmigiano-Reggiano (I don't know how aged it is) which you will also find at WFM and like Whole Foods, pretend-Parmesan from either N. or S. America. You can find Parm-Reggiano at most supermarkets these days (except Safeway or Rodman's, perhaps), but most charge a lot more than TJ let alone WFM.

Kraft proudly proclaims its product to be made from natural ingredients: milk, etc. It doesn't add the bit about the kinds of preservatives and anti-caking agents it adds to the mix.

I have to agree with everyone that suggested buying a block of Parmigiano Reggiano and a microplane. A block (as opposed to the grated stuff) has a lower surface-to-volume ratio and less of a chance of spoilage. Grating with a microplane will grate it so fine, that the cheese seems to liquify as soon as it hits the pasta or soup. ATK did thing on selecting cheeses.

I use the mini chopper from my Braun stick blender to grate the cheese on demand, when I need a bunch for a recipe or feel like spooning freshly grated cheese to finish a dish. Leftover grated cheese is stored refrigerated, in the same container, with the base becoming a lid. I also have a microplane, and a circular grater.
The remaining block is stored in the refrigerator in a plastic bag. I've never had a problem with the plastic with regard to mold forming, but am wondering if using the wax paper/foil cover is better for taste.
Thoughts?

Mold has to be a concern any time you attempt to store a cheese, even if you refrigerate it, and no matter what kind of cheese it is. I have had mold appear on a block of Parmiggiano-Reggiano that was double wrapped in ziplock bags and stored in the coldest part of my fridge. Granted, it was a large block (hey, I shop at Costco) that had been in the fridge many, many months, during which I had periodically unsealed it to carve off a smaller working chunk. But I did indeed get mold. Perhaps it somehow got exported from one of the other chunks of odds-and-ends cheese that I always have wrapped and stored in the fridge. (I tend to use cheeses mainly as an ingredient rather than as a destination food, and stores never sell the exact amount you need for whatever it is you're making. This is a product of the same conspiracy that produces hot dogs in packs of 10 and buns in packs of 12.)

But you know what I did to solve this problem? One day in Costco I bought a FoodSaver. It costed around $125, IIRC. Now I vacuum pack all my leftover bits of cheese, and have had no mold whatsoever. I'm sure I eventually will make back the cost of the FoodSaver just on the savings from not having to throw out moldy cheese, if I haven't already. And there are dozens of other food applications where vacuum packing makes sense, even if you don't venture into sous vide cooking. (You could certainly vacuum pack grated Parm Reg cheese, and might even be able to get away with not refrigerating it - but I think I would keep it cold myself just to be sure.)

And I second the recommendation on using a microplane grater on ParmReg. That has to be the most perfect kitchen tool ever invented - although from what I've heard it wasn't invented as a kitchen tool but rather imported into the kitchen from HomeDepot by some enterprising chef.

The Microplane was originally a carpenter's wood rasp. Now the company makes many, many more of them, and sells a huge percentage of what they manufacture for kitchen use instead of woodworking.

Click to view attachment

There are way to many people on this board admitting they own the green can.

I take no responsibility for the culinary sins of my parents.

I like there to be some texture left in the cheese, even when grated, and the Microplane obliterates it. For parm, I prefer a simple rotary (or drum) grater like the Zyliss, which takes a more "dimensional" shaving.

I assume most people are aware that Microplane makes many different kitchen microplane graters, coarse, medium, fine, very fine, box style, drum style, nutmeg grater, sliding attachment to avoid grating fingers, etc.

I like the medium ribbon style for parmesan to sprinkle on salads, and the coarse original style grater for parmesan to sprinkle over pasta. When the cheese gets smallish, pop it into the grater attachment, which is also good for garlic and ginger.

The old style spice grater grates nutmegs in a flash.

For enormous amounts of grated cheese or grated cabbage for cole slaw, the Cuisinart has several grating blades.

I don't even use my old box grater anymore.

One the subject of moldy cheese, I keep cheese in a separate refrigerator drawer, actually a meat drawer, all by itself. This drawer is soaked in a 10% solution of chlorine bleach a couple times of year to kill mold. I've tried wrapping hard and firm cheeses such as parmesan or cheddar first in a paper towel soaked in vinegar before wrapping in plastic wrap, with mixed results. It seems to work for a while but eventually stops working if you don't renew the vinegar wrapper.

One very good reason not to use pre-grated cheese is that if ungrated hard or firm cheese gets moldy, you can cut it off without worry, at least so says the USDA. Make sure to cut off a thickish slice of what looks like good cheese just to be safe.

I do give this to the dog, who seems to suffer no ill effects. Dogs have a short digestive system and can safely eat things that would make humans sick.

Does this affect the flavor of the cheese?

I certainly wouldn't use on a soft cheese but it doesn't add anything unpleasant to cheddar and other hard cheeses, in my opinion.

We use apple cider vinegar which has a mild, pleasant flavor. Any vinegar flavor remains on the outside.

The alternative is moldy cheese. I have some in my cheese drawer right now, need to feed it to the dog and soak the drawer in bleach water. Probably the spores have gotten into the air ducts, too. And this problem gets worse as the ambient temperature gets hotter outside.

How about non-grated cheese? I have a block of hard cheese that's been sitting for quite some time; it appears that only the rind (and immediately surrounding areas) has mold. Should I call Washington Hospital Center for pre-admission? Or, is it safe to eat once I cut off the fuzzy white stuff?

And... what about Feta? Again, sitting in the fridge for quite a while; I go through cheese/no-cheese phases. Does it ever go bad? It's kinda hard to tell which is fuzzy white stuff or the actual cheese. Or should I have WHC on speed dial?

Hard cheese is generally safe once you cut off the mold (the lack of moisture on the inside keeps the mold from spreading throughout).
Is the feta in oil or some sort of brine (probably ok)? Or just by itself (probably not)?

Can I brine store-bought, crumbled Feta? What would be the salt:water ratio?

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My guess is that the pre-crumbled stuff might get a bit salty since there's more contact area, but it's already a pretty salty cheese so you should be ok.

What I've seen is that you should cut an inch beyond the mold. I can't recall where I read that. I try to adhere to that but sometimes don't cut off that much.

Moldy smoldy! I just cut or wipe off any mold and have at it, hard, soft doesn't matter. Much to JPW's disgust. Of course, I learned that from my Dad who grew up during the depression and uses water to get the dregs of ketchup out of the bottle and who believes the sell by date is only a suggestion.