Not plume (which is mold), but most probably crystals of organic compounds (sugar, malate or else). But you should get some agar-agar to make sure, as you seem to have several problematic tins.
In focus photos, properly inserted into your post, would be helpful.
My guess would would be "Yes, it's mold", but it's damned near impossible to diagnose a lot of molds without actually seeing and culturing them. Precipitated minerals, sugar and additives such as flavorings and antifungal agents can all mimic fungus of some sort or another.