Last year on a HKG-JFK flight in F, during breakfast service, the FA set the bread basket and jams, etc. All the jam jars had the plastic seal around it unbroken so everything should be new. Opened up the strawberry jam, and a quarter of it was already scooped out. Not only that, there was a bit of butter and bread crumbs left in there which meant this was a previously used jar. I complained to the FA, purser, but not much they could do and not really their fault. Wrote to CX, zero response.