[avdlinde]

If the label contains sugar, it was added and not inclusive of other whole ingredients. You can buy canned apples (ingredients :apples) and canned apples (ingredients :water, sugar, apples). Guess which costs more.

[Broken_Hippo]

The nutrition label will tell you if it contains sugar even though none was added.

If the ingredient list contains sugar, it was added.

[rightbyte]

Why would you buy canned apples without sugar or vinegar as conservatives in the first place?

The pure apple in a can can't last for long.

[ryneandal]

I hate to be the pedant, but I think you meant preservatives. I kept imagining Mitt Romney in a tub with sliced apples and it was unnerving to say the least