I just ate accidentally ate some cheese with pink bacteria growing on it, will I get sick?

March 23, 2009 2:53 PM

I ate some cheddar cheese with a pink bacterial plaque growing on it, could this be something that'll make me sick?

I cut up some cheese for my lunch, some of it having been in my fridge for awhile. I was munching on the cheddar when I noticed it had a bit more smell than usual. I looked closely and saw some pink bacterial plaques growing on the surface.

I'm a biologist, but not a microbiologist, and I know that sometimes the e.coli and other crazy bacterias (we grow for the Introductory Biology lab I teach) can be pink. I also know that not all bacteria is toxic, not even all e.coli bacteria, but the fridge at my apartment has never been cleaned out properly and I know some weird stuff has been in there over the years.

Does anyone think it might be just an outgrowth of the normal lactic acid bacteria of the cheese? The bag the cheese was in was a little damp, which probably encouraged the growth. I threw the rest away.

If it is a bad bacteria, how long would it take for me to start getting sick?

posted by CTORourke to food & drink (18 comments total)

It's probably just fermentative lactic acid bacteria (biologist here, but I only work with B.subtilis and E.coli). Even if it's E. coli, the huge majority of strains are completely innocuous to humans. You have nothing to be worried about.

If it was something that can make you sick, you'd know by now.
posted by halogen at 3:00 PM on March 23

Well all cheese has bacteria as you know, so it does sound like it was fermenting a little. If it was just a bit stronger or 'cheesier' than you expected, like older cheddar or some super-strong crazy French cheese that that seems a safe guess.

Next time remember to use AskMe correctly: always ask FIRST.
posted by rokusan at 3:10 PM on March 23 [1 favorite has favorites]

Something on pink mold from an earlier question....
posted by Morrigan at 3:10 PM on March 23

If it was just a little bit, you'll probably be fine.

When I worked in cheese at Whole Foods, we were taught that it's fine to scrape white, grey, green, or blue mold from the surface of cheese (cheese that was not designed to be moldy, of course), but to chuck pieces that showed pink mold. I can't remember now why, though.

For your future cheese-wrapping needs, wrap the piece tightly in plastic wrap. If you have a dedicated cheese drawer in your fridge and go through cheese reasonably quickly, use wax paper instead.
posted by rtha at 3:11 PM on March 23 [1 favorite has favorites]

rtha: good suggestion on the plastic wrap, I never thought of that. They probably told you that because if it's pink, its likely a bacteria. What we tell our biology classes is that whitish grey or greenish plaques are mold (fungus), and yellow, white, or pink plaques are bacteria. Also, mold has a fuzzy look ("fungus is fuzzy") and bacteria is shiny.

And in my defense, i didnt KNOW the bacteria was ON the cheese until I had already eaten half of it ;p
posted by CTORourke at 3:23 PM on March 23

That's okay - I was once two slices into a cherry pie before I realized it was moldy. Made me sad, but not sick. Strengthening our immune systems is what we're doing!
posted by rtha at 4:07 PM on March 23

If you aren't puking right now, you'll probably be OK. Call an ambulance if you start hallucinating. I don't know what pink is, but it could be something non-trivial.

When I worked in cheese at Whole Foods, we were taught that it's fine to scrape white, grey, green, or blue mold from the surface of cheese

Gross! At least in Illinois, this is against food safety code. (For large wheels, there might be an exception that lets you cut off a certain large portion and still sell the rest, but I don't remember it.) Cheese that shows mold when it shouldn't is contaminated. Mold doesn't just grow on the surface, it gets into the body of the cheese. Maybe it's safe, maybe it's not. The store does not have the facilities to test this.

And quite frankly, for the prices Whole Foods charges, even if it were legal, it would be unacceptable.
posted by gjc at 4:07 PM on March 23 [1 favorite has favorites]

This is California, gjc, and on big pieces/wheels.

Cheese is alive. It grows things sometimes. If cheese mold were deadly, France wouldn't exist.
posted by rtha at 4:18 PM on March 23 [7 favorites has favorites]

Anecdatum: I once had a piece of cheddar cheese that had developed a small pink spot on the surface. I took note of the spot and meant to cut it off before eating the cheese, but then I inadvertently set the cheese spot-side down on a plate, sliced it, and ate it all before remembering about the spot. About twelve hours later, I woke up with a fever and all the unpleasant purging effects of food poisoning.

I have always hoped that the mysterious pink spot was to blame, because if it wasn't, then the next most likely culprit would be my own cooking (perish the thought).

But I hope the pink spot on your cheese won't make you sick!
posted by Orinda at 4:46 PM on March 23

Yeah, I would be a little worried about pink stuff on cheese. If you start getting sick then of course you should see a doctor, but I've read that if you've eaten something a bit dodgy and you're worried alcohol can help. As in "bottoms up", not the rubbing kind. I'm not sure if there is any scientific evidence to back this up, but there it is.

Lastly, if people are worried about still eating/serving cheese that was moldy (the fluffy king not the pink kind) and has had the mold cut off please get in touch. I'd be happy to eat it.
posted by ob at 5:11 PM on March 23

Cheese is alive. It grows things sometimes. If cheese mold were deadly, France wouldn't exist.

So am I. By your logic, this oozing infected sore on my foot should be just fine and I shouldn't worry about it? I'm alive, it's alive, we should all just get along? I can eat this moldy pizza? It's got cheese on it!

No, cheese isn't alive. It's curdled milk with bacteria in it, that happens to taste good. Mold on cheese can come from anywhere. Good cheese mold is inside the cheese and is put there by the cheese-maker because that's what's supposed to be in it. If it's on the outside of the cheese, it came from the air and lord knows what it is. It might be a cure for cancer, but that's not what it says on the package, and thus cannot be legally sold.
posted by gjc at 5:23 PM on March 23

If it's on the outside of the cheese, it came from the air and lord knows what it is.

You've heard of Brie, right? Camembert?

Modern, mass-produced Brie is, of course, deliberately innoculated with a specific kind of mold. But it's not exactly wrapped in plastic to age - the wheels are left open to the air.

There are also a zillion kinds of goat cheeses that are moldy on the outside (and sometimes inside, too).

By "alive" I meant that it changes. It doesn't go from edible to inedible because of some mold. It ages. It changes flavor and texture. I once forgot a lovely fresh goat cheese in the back of my cheese drawer for....several weeks. More than a month, certainly. It was wrapped in cheese paper. When I found it, I unwrapped it, smelled it*, cut into it, and had the pleasure of eating a cheese I had aged myself. It was ten times more delicious than the fresh version, which was itself pretty fucking ambrosial.

*If cheese ever smells like cat pee, don't eat it. If it's a big hunk of something like Cheddar, try wiping the surface with white vinegar - just dampen it - and then leave it in the open air for a while. If it still smells like cat pee, toss it. If it's a washed rind cheese, you can try the vinegar trick and/or you can cut the rind away very carefully, but really, I'd just toss it. It might not make you sick, but it won't taste very good.
posted by rtha at 6:00 PM on March 23

Pink doesn't automatically mean mold. There are several yeast strains that form yellow, cream, white, or even pink colonies. Unlike molds, yeast colonies generally look like bacterial colonies on a petri dish, with a smooth or even matte surface. Of course, common yeast strains (S. cerevisiae, P. pastoris, etc.) also have a distinctive and pleasant smell, so it's not likely that they were whatever was growing on your cheese.

(I'm not sure what sort of intro bio lab you teach, but knowing how to identify yeast as well as bacteria and molds might be useful for your students.)
posted by ubersturm at 7:09 PM on March 23

Rtha's footnote is spot-on. If a cheese smells like ammonia, toss it. I've lived in France, on and off, for a couple years, and regardless of the particular cheese, I found that the ammonia smell is the tell-tale sign of bad cheese. This in a land were the best cheeses are made from unpasteurized milk and sold at counters that would probably be shut down by most US health departments.

That said, I'd be wary of pink growth, though I have eaten a few slices of Muenster cheese that were pinkish around the edges with no noticeable ill effects.
posted by brianogilvie at 7:12 PM on March 23

Hey, eat whatever you want. But getting all cheese-strident and advising people to eat cheese (or selling it to them) that may or not be contaminated is just not cool. It's kinda like saying "go ahead and eat those wild mushrooms you picked yourself". You or I can't know what the effects will be, and while I probably would eat the moldy pizza, I can't in good conscience advise someone else to do the same. I'm sure the odds are good that it's fine. But you don't know that.
posted by gjc at 9:06 PM on March 23

To be sure, you might want to consider calling the Poison Control Center---number is at the front of your phonebook.
posted by ragtimepiano at 11:55 PM on March 23

Hey, gjc, you've expressed the Super Careful view, which is certainly the path a lot of people take. But it's not cool to stridently shout down the experience of other commenters here with vaguely accusatory language when, as you say, none of us can see or smell the cheese in question.

I'll offer that I've been gently scraping a pinkish bloom off of the chevre all week to no ill effect -- it is markedly different from the "bad" pink stuff that has caused me to throw out other cheeses.
posted by desuetude at 11:43 AM on March 24

@ ubersturm: It's an intro biology class for non-majors, so I can't get too technical. Really, its challenge enough to even get them to realize that yeast is a fungus. ;) They identify bacteria and mold because they go out, swab things in the building, then grow cultures on petri dishes, just to see whats there. But yeah, it's a good idea to point out that yeast may grow as well, since C. albicans is hanging out around our bodies already anyway.

Thank you everyone for the instructive comments in cheese-ology. I had no idea id spark such a debate, though. >.<
posted by CTORourke at 12:19 PM on April 23