I made some MMF at the end of October, it was sealed in Tupperware. I got it out today and it was a little hard so I microwaved it, re-kneaded it with a tiny bit of Crisco and it looks and tastes as good as new. Do you think it is still good to eat? It is only marshmallow, vanilla, and powdered sugar.
It's probably fine. I keep mine for a month or so. But if you think about fondant - it sits in containers for 6 months. So again, I'm sure that it's fine.
Yes it should stay good, but there is one important thing to consider about our homemade stuff vrs the commercial buckets.
There was a thread asking how long the buckets stay good for and a very prominent baker said months but to be sure to dip out the fondant you need with a clean utensil scoop of some kind and not your hands, and to not put back fondant that has been worked by hand. The preservatives are good but not good enough against outside contaminates.
I can't say how long it will last because I have never used old fondant. I prefer to make some fresh. I did leave some out on the counter wrapped in plastic wrap and then in a sealed container as suggested. I did not like the smell after a week. It was stale smelling. And I imagine working it by hand had something to do with it. And I have no idea if it would make any one sick, I doubt it but I also won't risk it. I don't sell cake either, just make for family and friends. I think freezing the stuff is the best choice to storing it as it suspends any spoiling.
I tried freezing MMF and it didn't work well. I have used MMF that's 2 weeks old and I think 3 or 4 is pushing it a bit. But that's stuff I've worked with...