Author Topic: Penicillium roqueforti - Very Tenacious!  (Read 2300 times)

Offline Baby Chee

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Penicillium roqueforti - Very Tenacious!
« on: January 19, 2010, 08:48:32 AM »
I wish I took a picture of this, because it would have helped, anyway...

A large chunk of my Gouda went under glass at room temp a couple weeks ago.  When I left for a while, I returned with the remaining portion COVERED in what seemed to be a blue mold.  There was no white, no black cat hair, just what looked like the mold on the outside of a Stilton.  It was a very fine level of even mold without other molds contaminating.

It appeared a little more greenish than a typical blue, but I think maybe that came from the cheese being a velveeta orange.

I tossed it all out, then realized later I might have had BLUE MOLD in the cheese.  Is this possible?  Maybe I didn't wash the pot out enough before making new batches?  Maybe some implement had blue mold on it?  Anyone have tales of blue mold?

Now I am curious about RE-AGING a large part of the gouda with that mold on the outside.  Any recommendations?

The gouda is a bland cheese, good for melting but really not a treat for eating.  It's a cheese and nothing more.  No inedible.  Could the blue refresh it possibly?

Or is this just some crap mold I am confusing with blue?
“For centuries, people thought the moon was made of green cheese. Then the astronauts found that the moon is really a big hard rock. That's what happens to cheese when you leave it out.”


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Offline FRANCOIS

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Re: Penicillium roqueforti - Very Tenacious!
« Reply #1 on: January 19, 2010, 12:32:58 PM »
That's why gouda is usually washed in heavy brine and then waxed to age.  It's rind is perfect breeding ground for all sorts of mold.  It could have been a wild blue.

Offline linuxboy

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Re: Penicillium roqueforti - Very Tenacious!
« Reply #2 on: January 19, 2010, 12:52:39 PM »
Hard to tell what sort of mold it is without pics. But I agree with Francois. Gouda is high moisture and low pH (washed curd). It is very vulnerable. Swiss-type cheese is similar in that the pH is even higher, but the moisture is lower, and propionic acts as a preservative, so it's not quite as bad.
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Offline mtncheesemaker(Pam)

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Re: Penicillium roqueforti - Very Tenacious!
« Reply #3 on: January 19, 2010, 01:53:19 PM »
Thanks for this topic! I have been meaning to ask about that darned blue mold, myself.
I get blue mold on every cheese I make, except Camembert. I seem to be able to control it best on the hard cheeses by rubbing the rinds with salt. But the softer, unpressed cheeses, like tomme, tallegio and muenster are giving me fits.
Although I wash these cheeses with brine, the blue mold comes right back. I finally knocked it back on a recent tomme, but I think that was in part due to competing molds.
Any help would be really appreciated. I think I'll always have the blue mold, but any tips on managing it would be greatly appreciated.
I practice good house-keeping and age in plastic boxes; the blues aren't with any other cheese types.
Thanks in advance,
Pam

Offline FRANCOIS

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Re: Penicillium roqueforti - Very Tenacious!
« Reply #4 on: January 19, 2010, 03:15:05 PM »
Dose your washes with natamycin at a rate of 5-20ppm.  No more blue mold....


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Offline Baby Chee

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Re: Penicillium roqueforti - Very Tenacious!
« Reply #5 on: January 19, 2010, 03:29:14 PM »
I'm leaving a small chunk out under glass to see what happens... assuming I don't eat it.

It was odd, because usually stray molds on past cheeses were a variety of colors and shaped.  This was a consistent blue-ish mold, so I wondered if it came from inside the curd itself.  Plate, glass cake dome, all sanitized.  So the cheese and air were the only factors in contamination... well, the knife too, I suppose, but the mold didn't spread from knife cuts, rather from the top surfaces.
“For centuries, people thought the moon was made of green cheese. Then the astronauts found that the moon is really a big hard rock. That's what happens to cheese when you leave it out.”

Offline Sailor Con Queso

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Re: Penicillium roqueforti - Very Tenacious!
« Reply #6 on: January 19, 2010, 09:33:51 PM »
Blue mold is naturally occurring everywhere. Is there anyone here that HASN'T seen it on moldy bread? Ironically, making blue cheeses greatly multiplies the number of spores and active organisms. You can pretty much count on every cheese being "contaminated" to a certain degree. Cleanliness and good rind management will go a long way, but those blue spots are still going to show up. I find that repeated wipings with brine seem to make a tougher, thicker rind so I use vinegar to wipe mold off.

Mold needs a good supply of oxygen to grow, so the interior of hard cheeses is not a concern. I age my cheeses naturally for about a month and then vacuum bag. No air, no problem.
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Offline mtncheesemaker(Pam)

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Re: Penicillium roqueforti - Very Tenacious!
« Reply #7 on: January 20, 2010, 08:48:11 AM »
Hey, Sailor,
Does the vinegar inhibit the molds you're trying to grow, like B. linens and others? I've used a vinegar/salt combo for hard cheeses where I don't want any mold successfully. It's the ones where I want other molds besides blue that are the problem.
So far I can't bring myself to wrap cheese in plastic.
Thanks,
Pam

Offline Sailor Con Queso

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Re: Penicillium roqueforti - Very Tenacious!
« Reply #8 on: January 20, 2010, 03:35:46 PM »
Yes it would inhibit other molds as well. I'm sure that's true of Francois' suggestion with Natamycin as well. The best scenario is for the B. linens to quickly out-compete the blue.
A moldy Stilton is a thing of beauty. Yes, you eat the rind. - Ed
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Offline FRANCOIS

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Re: Penicillium roqueforti - Very Tenacious!
« Reply #9 on: January 20, 2010, 04:36:22 PM »
There in lies the quandry.  You need perfect conditions to get the b. linens started, as well a dosing the milk, otherwise the blue will start before the b. linens can choke it out.  It's safer and easier just to use natamycin.


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Offline Brie

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Re: Penicillium roqueforti - Very Tenacious!
« Reply #10 on: January 20, 2010, 07:59:08 PM »
Well, what the heck is natamycin?
Darn, another cheese meltdown--ahh, perfect fondue.

Offline FRANCOIS

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Re: Penicillium roqueforti - Very Tenacious!
« Reply #11 on: January 20, 2010, 08:22:15 PM »
http://en.wikipedia.org/wiki/Natamycin

It's on Glengarry's website:
http://glengarrycheesemaking.on.ca/wax.htm

She has it for $110.00CN for 100g.  That's a bit pricey.  Effectivity is 5ppm though.

Offline Brie

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Re: Penicillium roqueforti - Very Tenacious!
« Reply #12 on: January 20, 2010, 08:39:17 PM »
Very informative thread. I made some brie last week, and added a pinch of B. Linens to the milk; yet somehow blue mold started forming along with the white on the surface. Scraped all surfaces, brined for a half hour, dried and sprayed on some P Candidum/Geo--we'll see what happens.
Darn, another cheese meltdown--ahh, perfect fondue.