In English "juice bottle" implies empty bottles which are intended to contain juice, but it looks like in Romanian it could mean either the just the bottles for juice or full bottles of juice. The person writing the question and answer might not have noticed the ambiguity yet?
Ah, ok... I can see that. Then, in that case, context (which is often missing in these over-simplified translations) may come into play. A bottle of juice implies that the bottle is full of juice when collected, whereas a juice bottle would be a likely empty bottle which had contained juice before it was emptied.