A dwarf is cooking using an ingredient with no name or description, and there are a few roasts in the fortress using that ingredient. I have no idea where it came from. Maybe the human traders, or maybe dwarves being horrified by the corpses in the refuse stockpile as they walk by could have done something to fishing, herbalism, or outdoor farming. The ingredient is listed in the kitchen status between the fish and the seeds. I only caught this when there was one of that object left.