Bad Molds, Good Molds and Cured Meat – Pictures too

When it comes to curing meat especially dry-cured meat over a few months or more, the aspects of mold are one of the more challenging hurdles I’ve found in the beginning.

There’s not a lot of detail online or in many of the meat curing books that I’ve read about the good mold and the bad mold. So I hope this helps!

When I started doing dry-cured meats, I didn’t use any type of starter culture, which is one method for inoculating the curing chamber to create the right environment at the start.

I purely went down the natural path and was willing to leave it in the hands of nature to decide whether things would progress or not. This was nearly 20 years ago!

Dry curing meat, specifically, has been going on for thousands of years, and good old-fashioned common sense played and plays a big part in successes and failures.

Common sense and logic and trusting you’re built-in instincts about whether the food is good or not will help a lot. There is definitely now a lot more detachment from the natural world with all our glorious technologies including blogs!

Here is a summary first about molds and then I will tell you about what I have learned in relation to doing it at home.

Dry Cured Meat Penicillin White Mold
Blooming good penicillin mode on wild venison braesola!

What are Good and Bad Molds for Cured Meat? Good Mold is predominately white either powdery or fluffy. Certain Green colors can be good molds and are related to the penicillin white mold also. Orange, Red needs to be removed, whilst black mold is definitely bad.

Purpose of Good Mold for Meat Curing

For many dry-cured meat projects, a minimum drying period is a one-month plus. Normally it takes a couple of days or a week before you start to see blooms of mold on meat depending on where it was hung (chamber/cellar etc. )or cold smoked.

Developing a good covering of powdery white penicillin mold on the outside of dry-cured whole muscle meat or dry-cured salami is the goal.

Temperature, Humidity, Airflow, Existing Mold Culture, and lack of light are the general environmental factors relating to this.

The white mold is a way of protecting the meat for certain recipes.

Other recipes such as Calabrian pancetta covered with pepper and chili/pepperoncino. External spices are used to deter the growth of mold.

Peppercorns & black (I think red, white, etc too) pepper have antibacterial and antifungal properties.

The Funkiness

Dry-cured meats can create what some call the funk.

It’s really hard to describe the funk unless you have smelled or tasted it.

I think it would vary as well depending on the environment and how the moldable funk has developed. My thoughts are that the mold has a lot to do with the funk!

It’s probably part of the reason why over all these years I am still completely fascinated with dry curing meat, there are just so many subtle variations going on.

On a side note recently I’ve been thinking about cold smoking spices and using those for dry-cured meats. I’ll do some research around this and report back on this blog

The Flavor of Good Molds

Early development of white mold

Yes, this is the same kind of mold that is used in medicine and hospitals from what I know.

It is that fluffy or powdery white mold known as penicillin.

It can be a purchased starter culture that you then inoculate the meat curing chamber with.

Or a naturally occurring white penicillin mold or good mold.

I would say the taste and smell are relatable to the type of umami or savory flavor.

One of my friends Lawrence, who I taught how to dry-cure meat absolutely loves the flavor of that white powdery mold on the outside of his wild pig guanciale.

Commercially dry-cured meat with a bloom of white mold, you can see the healthy fuzz! (Photo made my camera look blurry!)

Molds and Using Your Senses

I talk a lot about using your senses in my online meat curing course, it is one of those obvious things but like many things, it’s good to be reminded of.

That is, we have an evolutionary naturally developed ability to work out from smelling and looking at food whether it’s going to be good for us or not (not all the time, but in most cases).

I am guilty of getting my nose right up next to the dry-cured meat and giving it a big sniff. This gives me an indication of how things are going. I will continue to sniff all around that whole piece of meat!

The notorious bald-headed salami sniffer – what a speciman!

There is quite a bit of complexity that can happen with the smell of salami or of a whole muscle piece of charcuterie while it develops, again, this is why I find this craft so fascinating!

Natural Molds and Lab Mold

Using a lab starter culture, provides more consistency, as long as the conditions are right

Supposedly good old penicillin is floating around all over the place, and once you have finished curing with salt.

Your piece of meat has a chance, depending on your environment, that the naturally occurring penicillin will start on the meat. I’ve done this several times over the years with new DIY meat curing chamber I’ve put together.

But of course, this is not guaranteed.

Commercial producers of dry-cured real salami, the stuff that takes months to make not the tangy acidic stuff that is made in a few days often are using this culture to make outcomes consistent.

They buy stuff and inoculate the salami or whole muscle meats themselves.

Mold 600 – Bactoferm

Home charcuterie makers and many other producers use CHR Hansen mold 600 for whole muscle meat curing inoculation.

There are plenty of starter cultures, but many are doing a similar function for say salami ie. acidification (a key tool for making salami preserved and creating good outcomes).

Mold 600 is more about the outside of the meat whilst it’s drying.

I have it sitting in my freezer now, you can’t get it in every country be most countries in the western world. There are probably also other names it may have.

Guys have contacted me through the blog about trying to ‘scrap’ commercial traditional salami they buy to inoculate their own DIY curing chambers!

When I need to use it, I take half a teaspoon to half a cup of water. The water should ideally be distilled, but I’ve used filtered water which has worked as well.

Then you leave it for eight hours on the bench after giving it a bit of a shake and then spread it in the chamber onto cured meat. Within a few days, you should start to see the spores of white mold developing.

Check out mold 600 from Amazon here.

Development of White Molds Over Time

So a lot of people just go on about the powdery mold but when you start learning more about dry-cured meats, you’ll notice that at the beginning you might get fluffy mold.

An array of Good Mold!

But really underneath that fluffy white mold is powdery mold it’s just the way that it grows.

Then down the line, as the mold gets older there is a green mold related to the spores of the white penicillin mold.

Dark green mold in a commercial environment down the bottom of Italy in Calabria.

Green mold is fine, but this is also a hog bladder for a spreadable salami called Njuda in Calabria, Italy. The casing is not consumed, well I don’t think it is!

Molds I Can Deal With

Now I have had some funky molds going on here are a few examples of things that were not good not bad but also what you don’t really want.

So I just wipe it off with vinegar.

When it’s developing on a case think it’s not so much of the big deal, because you’ve obviously got some protection on the meat.

When you’re using no casing and going natural which I often am because I like to see exactly what’s going on. Using vinegar and wiping the mold off or even giving it a blast of cold smoked for a few hours can knock back some of this unwanted multi-colored mold.

Bad Molds – Black

Examples of fuzzy good mold, good green mold – and something that made me throw it out! 1 of 2 pieces I have thrown out over a few decades of making dry-cured meat.

There is a certain smell and a look that I’ve only had a couple of times over a few decades and that is the ominous black mold.

It kind of looked a little bit translucent and it was on some very exotic spices that I used, whether this was a factor or not I do not know.

Spices like star anise, coriander, cumin, and galangal were used. And there was this patch of what I would consider black mold.

The smell was very offputting and instantly my olfactory system said this needed to go straight into the rubbish bin.

Mold – Final Notes

Charcuterie Salumi Dry Cured Meat Picture
Charcuterie Salumi Dry Cured Meat – from my standard kitchen fridge. Only 1-month project, and no mold really.

I try really hard in my online meat curing course to go over mold and pictures and smells in the videos. But also at the end of the day, you need to go through and have your own experiences about what the good stuff should look like.

Always be on the side of caution and keep it safe! If you have to question it, it’s probably not worth risking it for the biscuit!

Put differently, if you had any doubts about anything you’re making it’s not worth getting sick from, and you should always be on the side of conservatism.

If you’re not completely happy with what you produce then throw it in the bin!

Cold Smoked Dry Cured Bacon, after 2 months in curing chamber. No mold because it’s been smoked and then hung to dry.

Something also I’ve noticed, when I had a dry curing chamber power cut, it reset to a fridge temperature. The Hungarian salami that was hanging, did have some white mold. Since I didn’t notice the wrong drying temperature.

I changed it back and after a day or so, the white mold was gone (back to 12C or 55F approximately). Lower temperature could be used to knock back mold that isn’t wanted!


  1. Perhaps you can help. I am curing some pepperoni in UMI BAGS. Been in refrigerator since 3/22. It is now 0.71 its original weight. I noticed some white spots with green in the middle of each dot. Should it be discarded? New at this so a bit insecure. Do you have any advice?

    1. Author

      Hey there,
      often I find white and green completely fine, have a sniff! can wipe with vinegar if you want. You’ll find out when it’s done! Nothing is guaranteed with dry curing, thats why i love it!

      1. I am having the same thing. .79 weight loss using the dry aging bags, and I have a bunch of good white mold showing, but some spots 1/4 inch across that have a grey/green/blue color to them in the center of the dot. If you email me directly, I can send you a pic.

        1. Author

          Havent tried those bags, but been talking to some of those companies to see if I can test them. Your Nose will also indicate the molds that you want or not. Wipe with vinegar if its on the outside Cheers Tom

  2. Hello, I’m trying to make my first pancetta. After some time in the fridge, and a few days of my abscense it developed white mold like this:

    I asked around and some people told me to wipe it with some vinegar, after the process it looks like this:

    I’m not sure about the dark spots, do you think is okay or should i throw it out? The meat itself smells fine.
    Best regards

    1. Author

      Howdy Jan
      Always hard to judge this type of thing from pictures….
      How Does it smell? like you want to eat it or not?
      What method of curing the meat did you use, eq curing? %’s?, time in cure? how long in cure?
      Where was it dried and what temp, humidity and airflow?
      how firm was the meat after curing?
      There are plenty of cuts/crevices in the meat, did you put dry cure in these?
      White mold is of course what you want, so what did that white mold smell like?

      It doesn’t look like it has lost 30%+ weight, did it?
      I have a course also about whole muscle dry curing here
      All the best

  3. So just checking we have some speck that was probably stored incorrectly and I think it was sweating now it has white and green mold on the surface and smells funky. Can I was it off and cut the outside and eat it? Or is the smell test saying no?

    1. Author

      Hey, I can’t do the smell test for you 🙂 In my experience, white/green like what I show is a good mold. But you have to make the call on that one. People always think dry cured meat belong in fridge, if uncovered the dry environment dries it out fast. If it’s in a container, I have had the same, moisture can create issues.
      It best to actually just hang it somewhere around the house in a temperate environment. Like an Italian deli! All the best, Tom

    1. Author

      Interesting, email me a pick if you want. But honestly, I haven’t ever got yellow mold. Over the years, many say all is good as long as it’s not black! 🙂 trust your senses! Cheers Tom

  4. Hi Tom,

    Thanks for everything you put up her, its so helpful!
    I have just got some coppas out of cure and want to briefly cold smoke them before putting them into my maturation chamber. Will the low pH of the smoke permanently stop the growth of mold once the meat is in the chamber or will it just delay it?

    1. Author

      Hey no worries,
      I’ve found, the cold smoke definitely knocks back mold. I recently had cured pork belly/pancetta I decided to cold smoke for 2-3 hours before hanging. But I lay the pork belly on a rack. It didn’t grow nice white mold where the meat was touching the grill and not exposed to the smoke! That was interesting indeed. Dry out for a bit of a pellicle if need be, before cold smoking. Tacky dry outside allows smoke vapor to adhere to it more! Cheers Tom

  5. Hi Tom. Great insight here and I’m just finishing my first batch of salami. The white mold has turned green on a few which I’m ok with but on one or two it’s turned into a pale pinky colour. Doesn’t smell off in anyway. Thinking I should wipe it off and see what it smells like when sliced ? Have you come across this before?

    1. Author

      Thanks! What in the recipe? I’ve sometimes got a bit of pinkish kind from humidity being too hight. I just wiped it off with a dap of vinegar! Want to encourage that ‘good’ mold! 🙂 Cheers Tom

  6. Hi Tom, i did a Dry Aged rack of pork and on the outside i noticed some green on the pellicle, i trimmed it off because it was todays deadline 28 days, the colour is promising on the inside but i’m concerned that the mold affected the whole meat. Look foward to hearing your answer.

    1. Author

      I am talking cured meats in this post not dry-aged, so meats that are fully salt-cured. I have a dry ager but haven’t tested it out. Watch this space! It has dry curing functionality which I am currently using.
      How does it smell? That’s the first thing, if it was smelling ok, I would chop off the green.
      In this post, I am talking about advanced penicillin white mold, which is green. Not sure how this relates to dry aging.
      Sorry, but dry-aging is not what I do, I wet age wild meat normally like venison.
      All the best,

  7. Hi, I’m not a meat curer! I bought serrano ham last year december ’21! it didn’t get eaten, it was stored dry. Then we cut it but my husband decided he didn’t want it as he was put off by the leg. I then cut it up in January ’23 in smaller pieces and stored them in mylar bags. I went to check on them just now and they have a film of wite mold. I kept it for the dogs, as treats, but not sure now if it’s safe. How long will it kerp and is that slightly slimy white mold safe? ( Iwill scrape it if it hasn’t spoiled the meat) is there another tip how I can find out if the meat is safe? Thank you

    1. Author

      Was it vacpacked in the bags? was it stored in a fridge? if yes and yes if yes, i would eat it.
      I wouldn’t give much at all to animals since the salt content is a bit high for the poochys
      ps. some serranos are dried for 5 years!

  8. Hey tom its jono from Pici and we picked olives with Jane in puglia i cant find your new number flick me a txt on 0224344519 for a catch up

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