How did this mold get into my cheese?

[nym]

This is my first post to the forum and I'm a beginner cheesemaker so please be gentle!

I decided to have a try at making a Stilton-type cheese by following Gavin Webber's tutorial at https://www.youtube.com/watch?v=k2dXcMm6S40
My first attempt went pretty well. I followed the instructions as best as I could except that I did not add the Penicillium Roqueforti because I didn't have any!
I aged the cheese for about a month in my kitchen fridge (~5degC) at which point there was a little blue mold on the surface and on cutting the cheese, I found a very little more blue mold below the surface at the points where I had pierced the cheese. Of course, I hadn't expected to find any mold as I hadn't added the Penicillium Roqueforti.

My first cheese tasted pretty good and I was quite proud of it and decided to have another go. I followed exactly the same procedure  (except that I didn't bother piercing the cheese as I still hadn't bought the Penicillium Roqueforti!). Also, I aged the second cheese for about two months in a slightly warmer fridge (~10degC). When I cut into the cheese, I was surprised to find an abundance of mold throughout the interior. The taste and texture of the second cheese was good in places but where the mold had grown particularly strongly, the taste was 'dusty' and rather unpleasant. I didn't eat those bits and I've ended up throwing quite a lot of it away 

So I'm wondering what happened. I assume that wild mold spores must have got into my second cheese somehow although I followed exactly the same procedures for sterilising equipment, worktops, hands etc. How was it able to grow so strongly? I thought that molds needed oxygen to grow?
Any thoughts or advice?
I've attached an image to this post but it's not showing up on the preview so I hope that I've done it correctly!

Many thanks

[Frodage3]

Hi Nym,
Welcome to the forum. That is a nice looking cheese! It must be a wild strain of mold that got into your make. For the next one, you might consider adding a chunk of bought blue cheese. That way you would get a starter culture of P. roqueforti without having to buy the mold powder. Have a cheese from me for your efforts!

[Schnecken Slayer]

What process did you use to sanitise the equipment?
Since you didn't pierce the second one the mold has to have gotten in during the make or the forming which says something wasn't clean enough.
I put all my equipment, pots, moulds, stirrers, cutters etc. through the dishwasher as it sanitises extremely well and use it straight away.
(The cheesecloth I soak for 20 minutes in a sanitising solution.)

I have only had unwanted blue show up on the outside of a cheese and tracked that down to my opening the wine fridge door after turning my blue. A simple wipe down with straight vinegar fixed that problem. 

[nym]

Thank you both for the kind words and advice. It's unfortunate that the cheese I made was not at all what I intended!
Regarding sanitisation, I used the same procedure for both cheeses. That is, I boiled the utensils and cheesecloth in the large pot that I used to make the cheese and I sprayed the work surfaces with sterilising solution.
I clearly wasn't careful enough when I made the second cheese. Using the dishwasher is a good tip and I may try that next time.

[awakephd]

I'm going to go respectfully disagree with the others, and suggest that sterilization is not the problem - what you describe should be more than adequate. The problem is 1) wild blue mold is everywhere, and is very aggressive, and 2) you didn't "out-compete" the wild mold with the desired mold.

Keep in mind that, unless you make cheese in a bio-filtered clean room, you cannot escape wild mold and bacteria, present in the air, from getting to your cheese at every stage of the process. One second after your utensils have cooled down from boiling or dishwasher or anything else, they are now becoming infected. While you are gently heating the milk, all sorts of mold and bacteria are finding their way to the surface. As you mill it into curds ... you get the idea.

As I understand it, sterilizing IS important, not because it eliminates any of this wild air-borne bacteria/mold from getting to your cheese, but rather because 1) it eliminates contact-borne nasties like E. coli, and 2) it keeps the undesirables from getting too strong a hold up front. You want to give room for the desired bacteria (and mold, if that is part of the make) to take hold and develop, so that they can out-compete the undesirables. In other words, if you start out with the undesirables "in control," your desired bacteria/molds are going to have trouble doing their job.

As for the mold inside your second cheese ... mold DOES require oxygen, regardless of whether it is wild or domesticated/desired. So the only way the interior of your cheese developed so much mold is that there were sufficient gaps and cracks between the curds to allow it to develop. In a typical blue cheese, piercing reinforces what should have already started with the gaps and cracks, allowing more oygen in for more development. And again, wild blue is EVERYWHERE, and it is super aggressive - and by the time your cheese is sitting in the cave, sterilization is long since past.

All that to say - get thee to a cheesery and buy some P. Roqueforti! I buy most of my supplies on-line from Artisan Geek, and there are several other good vendors. The P. Roqueforti may seem expensive up front, but a little bit goes a long, long way, so it really is very inexpensive on a per-cheese basis.

[nym]

Hi Andy

Thanks so much for your considered response. What you say sounds eminently sensible - none of us have access to a NASA-style clean room!
But I suppose that I'm still  left wondering why my first cheese was OK and only showed signs of mold growth close to the piercings and not throughout the whole cheese...
Time for another attempt I think. And this time I'll add the P. Roqueforti 

Many thanks to all who have responded to me. This forum is a wonderful resource. I'm sure that I will be back with more questions.

[Fritz]

Isn't it funny... We try so hard to make a picture perfect cheese like the one above... Following detailed ingredients, recipes, techniques and process ....just for one to "accidentally" appear for nym without even trying !

I'd pay big bucks for a blue that looks that good ! Too bad about the strain of mold... Upon close inspection, I see loose curds on the interior and fissures that extend to the surface of the rind. That is where it probably originated from common blue spores ...maybe a less than dry wiping possibly resulted in liquid with spores seeping deeper into the interior .... And then ...well you know the rest....

I'll give a cheese to nym simply because of the beauty of a blue that never was.