Do floating fruits/ingredients tend to spoil or smell bad?

[EmptyGingerman]

I've got a simple closet wine recipe
1 litre of water
180ml of sugar
1.25ml of bread yeast or active dry yeast
and I also added 30gms of cut ginger cubes
I've tried this recipe with many other flavours, but ginger is the only one which has floating chunks and bits in it, I've lifted the lid just to take a whiff out of curiosity and it smell funkier than the others, so my question is, can floating bits spoil since they're not fully submerged in the liquid?
also can tiny particles stuck to the sides of the top of the bottle spoil as well?

 

[lumpher]

Absolutely yes. Anything exposed is subject to wild yeast and mold.

 

[IslandLizard]

Once fermentation has started, and alcohol is being created, you can swirl the fermentation jar somewhat, dousing the floating bits. That can help against mold forming or other microorganisms starting to grow, and spoil your beverage.

Having a decent seal on the lid and a good working airlock prevents oxygen from getting into your fermenter, while letting CO2 out. Many microorganisms including mold, need oxygen and dampness to grow. Prevent oxygen from entering and they'll have a hard time growing.

Now at the time of pitching the yeast, having some dissolved oxygen in your juice is useful, as yeast needs it to grow (multiply).
You can simply shake it, stir, or pour hard to aerate the juice. Once the yeast has used up the oxygen, no more is needed or even wanted, except in some very high gravity brews, where a 2nd or even 3rd aeration/oxygenation can be helpful, all done before any alcohol is formed.